1196:. An alternating current is applied to the drive winding, which drives the core in a continuous repeating cycle of saturation and unsaturation. To an external field, the core is alternately weakly permeable and highly permeable. The core is often a toroidally wrapped ring or a pair of linear elements whose drive windings are each wound in opposing directions. Such closed flux paths minimise coupling between the drive and sense windings. In the presence of an external magnetic field, with the core in a highly permeable state, such a field is locally attracted or gated (hence the name fluxgate) through the sense winding. When the core is weakly permeable, the external field is less attracted. This continuous gating of the external field in and out of the sense winding induces a signal in the sense winding, whose principal frequency is twice that of the drive frequency, and whose strength and phase orientation vary directly with the external-field magnitude and polarity.
1165:; i.e., magnetised, unmagnetised, inversely magnetised, unmagnetised, magnetised, and so forth. This constantly changing field induces a voltage in the second coil which is measured by a detector. In a magnetically neutral background, the input and output signals match. However, when the core is exposed to a background field, it is more easily saturated in alignment with that field and less easily saturated in opposition to it. Hence the alternating magnetic field and the induced output voltage, are out of step with the input current. The extent to which this is the case depends on the strength of the background magnetic field. Often, the signal in the output coil is integrated, yielding an output analog voltage proportional to the magnetic field.
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against a spring. Commonly a capacitive load cell or cantilever is used because of its sensitivity, size, and lack of mechanical parts. Faraday force magnetometry is approximately one order of magnitude less sensitive than a SQUID. The biggest drawback to
Faraday force magnetometry is that it requires some means of not only producing a magnetic field, but also producing a magnetic field gradient. While this can be accomplished by using a set of special pole faces, a much better result can be achieved by using set of gradient coils. A major advantage to Faraday force magnetometry is that it is small and reasonably tolerant to noise, and thus can be implemented in a wide range of environments, including a
1520:
602:(VSMs) detect the dipole moment of a sample by mechanically vibrating the sample inside of an inductive pickup coil or inside of a SQUID coil. Induced current or changing flux in the coil is measured. The vibration is typically created by a motor or a piezoelectric actuator. Typically the VSM technique is about an order of magnitude less sensitive than SQUID magnetometry. VSMs can be combined with SQUIDs to create a system that is more sensitive than either one alone. Heat due to the sample vibration can limit the base temperature of a VSM, typically to 2 kelvin. VSM is also impractical for measuring a fragile sample that is sensitive to rapid acceleration.
1120:
1904:
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1221:, or superconducting quantum interference devices, measure extremely small changes in magnetic fields. They are very sensitive vector magnetometers, with noise levels as low as 3 fT Hz in commercial instruments and 0.4 fT Hz in experimental devices. Many liquid-helium-cooled commercial SQUIDs achieve a flat noise spectrum from near DC (less than 1 Hz) to tens of kilohertz, making such devices ideal for time-domain biomagnetic signal measurements. SERF atomic magnetometers demonstrated in laboratories so far reach competitive noise floor but in relatively small frequency ranges.
951:. When a caesium atom within the chamber encounters a photon from the laser, it is excited to a higher energy state, emits a photon and falls to an indeterminate lower energy state. The caesium atom is "sensitive" to the photons from the laser in three of its nine energy states, and therefore, assuming a closed system, all the atoms eventually fall into a state in which all the photons from the laser pass through unhindered and are measured by the photon detector. The caesium vapour has become transparent. This process happens continuously to maintain as many of the electrons as possible in that state.
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spacing at 100 m elevation, with readings every 10 meters or more. To overcome the asymmetry in the data density, data is interpolated between lines (usually 5 times) and data along the line is then averaged. Such data is gridded to an 80 m × 80 m pixel size and image processed using a program like ERMapper. At an exploration lease scale, the survey may be followed by a more detailed helimag or crop duster style fixed wing at 50 m line spacing and 50 m elevation (terrain permitting). Such an image is gridded on a 10 x 10 m pixel, offering 64 times the resolution.
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changing dc field), as occurs in capacitor-driven pulsed magnets. These measurements require differentiating between the magnetic field produced by the sample and that from the external applied field. Often a special arrangement of cancellation coils is used. For example, half of the pickup coil is wound in one direction, and the other half in the other direction, and the sample is placed in only one half. The external uniform magnetic field is detected by both halves of the coil, and since they are counter-wound, the external magnetic field produces no net signal.
1112:
1431:, coal mine hazards, unexploded ordnance, toxic waste drums, as well as a wide range of mineral deposits and geological structures. They also have applications in heart beat monitors, concealed weapons detection, military weapon systems positioning, sensors in anti-locking brakes, weather prediction (via solar cycles), steel pylons, drill guidance systems, archaeology, plate tectonics, radio wave propagation, and planetary exploration. Laboratory magnetometers determine the magnetic dipole moment of a magnetic sample, typically as a function of
681:. Faraday rotation magnetometry utilizes nonlinear magneto-optical rotation to measure a sample's magnetization. In this method a Faraday modulating thin film is applied to the sample to be measured and a series of images are taken with a camera that senses the polarization of the reflected light. To reduce noise, multiple pictures are then averaged together. One advantage to this method is that it allows mapping of the magnetic characteristics over the surface of a sample. This can be especially useful when studying such things as the
1415:
443:, consisting of a magnetized needle whose orientation changes in response to the ambient magnetic field, is a simple type of magnetometer, one that measures the direction of the field. The oscillation frequency of a magnetized needle is proportional to the square-root of the strength of the ambient magnetic field; so, for example, the oscillation frequency of the needle of a horizontally situated compass is proportional to the square-root of the horizontal intensity of the ambient field.
33:
1097:, nickel-iron alloy, whose electrical resistance varies with a change in magnetic field. They have a well-defined axis of sensitivity, can be produced in 3-D versions and can be mass-produced as an integrated circuit. They have a response time of less than 1 microsecond and can be sampled in moving vehicles up to 1,000 times/second. They can be used in compasses that read within 1°, for which the underlying sensor must reliably resolve 0.1°.
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185:
1279:. For the case of alkali, the coherence times were greatly limited due to spin-exchange relaxation. A major breakthrough happened at the beginning of the 2000 decade, Romalis group in Princeton demonstrated that in such a low field regime, alkali coherence times can be greatly enhanced if a high enough density can be reached by high temperature heating, this is the so-called
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665:. Faraday force magnetometry can also be complicated by the presence of torque (see previous technique). This can be circumvented by varying the gradient field independently of the applied DC field so the torque and the Faraday force contribution can be separated, and/or by designing a Faraday force magnetometer that prevents the sample from being rotated.
1814:. The iPhone 3GS has a magnetometer, a magnetoresistive permalloy sensor, the AN-203 produced by Honeywell. In 2009, the price of three-axis magnetometers dipped below US$ 1 per device and dropped rapidly. The use of a three-axis device means that it is not sensitive to the way it is held in orientation or elevation. Hall effect devices are also popular.
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stress-magnetisation relationship. However the effect of mechanical stress on measured magnetic field near the specimen is claimed to be proven in many scientific publications. There have been efforts to solve the inverse problem of magnetisation-stress resolution in order to quantify the stress based on measured magnetic field.
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118:) metals, but can detect such metals at a much greater distance than conventional metal detectors, which rely on conductivity. Magnetometers are capable of detecting large objects, such as cars, at over 10 metres (33 ft), while a conventional metal detector's range is rarely more than 2 metres (6 ft 7 in).
1671:, and magnetically-triggered mines. However, submarines are never completely de-magnetised. It is possible to tell the depth at which a submarine has been by measuring its magnetic field, which is distorted as the pressure distorts the hull and hence the field. Heating can also change the magnetization of steel.
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Recording data and image processing is superior to real-time work because subtle anomalies often missed by the operator (especially in magnetically noisy areas) can be correlated between lines, shapes and clusters better defined. A range of sophisticated enhancement techniques can also be used. There
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Submarines tow long sonar arrays to detect ships, and can even recognise different propeller noises. The sonar arrays need to be accurately positioned so they can triangulate direction to targets (e.g. ships). The arrays do not tow in a straight line, so fluxgate magnetometers are used to orient each
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The calibration of magnetometers is usually performed by means of coils which are supplied by an electrical current to create a magnetic field. It allows to characterize the sensitivity of the magnetometer (in terms of V/T). In many applications the homogeneity of the calibration coil is an important
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In the most common type of caesium magnetometer, a very small AC magnetic field is applied to the cell. Since the difference in the energy levels of the electrons is determined by the external magnetic field, there is a frequency at which this small AC field makes the electrons change states. In this
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using a solenoid, a low power radio-frequency field is used to align (polarise) the electron spin of the free radicals, which then couples to the protons via the
Overhauser effect. This has two main advantages: driving the RF field takes a fraction of the energy (allowing lighter-weight batteries for
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Faraday force magnetometry uses the fact that a spatial magnetic field gradient produces force that acts on a magnetized object, F = (M⋅∇)B. In
Faraday force magnetometry the force on the sample can be measured by a scale (hanging the sample from a sensitive balance), or by detecting the displacement
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Because hills and valleys under the aircraft make the magnetic readings rise and fall, a radar altimeter keeps track of the transducer's deviation from the nominal altitude above ground. There may also be a camera that takes photos of the ground. The location of the measurement is determined by also
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The main interest of optically-pumped magnetometers is to replace SQUID magnetometers in applications where cryogenic cooling is a drawback. This is notably the case of medical imaging where such cooling imposes a thick thermal insulation, strongly affecting the amplitude of the recorded biomagnetic
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on superconductors. Microfabricated optically pumped magnetometers (μOPMs) can be used to detect the origin of brain seizures more precisely and generate less heat than currently available superconducting quantum interference devices, better known as SQUIDs. The device works by using polarized light
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Magnetic torque magnetometry can be even more sensitive than SQUID magnetometry. However, magnetic torque magnetometry doesn't measure magnetism directly as all the previously mentioned methods do. Magnetic torque magnetometry instead measures the torque τ acting on a sample's magnetic moment μ as a
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methods are preferred to magnetometers as the primary survey method for oil exploration although magnetic methods can give additional information about the underlying geology and in some environments evidence of leakage from traps. Magnetometers are also used in oil exploration to show locations of
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Developed countries such as
Australia, Canada and USA invest heavily in systematic airborne magnetic surveys of their respective continents and surrounding oceans, to assist with map geology and in the discovery of mineral deposits. Such aeromag surveys are typically undertaken with 400 m line
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Large volume detectors have achieved a sensitivity of 200 aT Hz. This technology has greater sensitivity per unit volume than SQUID detectors. The technology can also produce very small magnetometers that may in the future replace coils for detecting radio-frequency magnetic fields. This technology
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Another type of caesium magnetometer modulates the light applied to the cell. This is referred to as a Bell-Bloom magnetometer, after the two scientists who first investigated the effect. If the light is turned on and off at the frequency corresponding to the Earth's field, there is a change in the
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At this point, the sample (or population) is said to have been optically pumped and ready for measurement to take place. When an external field is applied it disrupts this state and causes atoms to move to different states which makes the vapour less transparent. The photo detector can measure this
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of units. 10,000 gauss are equal to one tesla. Measurements of the Earth's magnetic field are often quoted in units of nanotesla (nT), also called a gamma. The Earth's magnetic field can vary from 20,000 to 80,000 nT depending on location, fluctuations in the Earth's magnetic field are on the order
1203:
Phase synchronous detection is used to extract these harmonic signals from the sense winding and convert them into a DC voltage proportional to the external magnetic field. Active current feedback may also be employed, such that the sense winding is driven to counteract the external field. In such
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popularised 'geophys', including magnetic techniques used in archaeological work to detect fire hearths, walls of baked bricks and magnetic stones such as basalt and granite. Walking tracks and roadways can sometimes be mapped with differential compaction in magnetic soils or with disturbances in
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measure the direction and magnitude of magnetic fields. Fluxgates are affordable, rugged and compact with miniaturization recently advancing to the point of complete sensor solutions in the form of IC chips, including examples from both academia and industry. This, plus their typically low power
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of a sample material. Unlike survey magnetometers, laboratory magnetometers require the sample to be placed inside the magnetometer, and often the temperature, magnetic field, and other parameters of the sample can be controlled. A sample's magnetization, is primarily dependent on the ordering of
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reference. Magnetometers are also used by the military as a triggering mechanism in magnetic mines to detect submarines. Consequently, some countries, such as the United States, Canada and
Australia, classify the more sensitive magnetometers as military technology, and control their distribution.
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are pairs of magnetometers with their sensors separated, usually horizontally, by a fixed distance. The readings are subtracted to measure the difference between the sensed magnetic fields, which gives the field gradients caused by magnetic anomalies. This is one way of compensating both for the
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Vector magnetometers measure one or more components of the magnetic field electronically. Using three orthogonal magnetometers, both azimuth and dip (inclination) can be measured. By taking the square root of the sum of the squares of the components the total magnetic field strength (also called
2013:
Some total field sensors give different readings depending on their orientation. Magnetic materials in the sensor itself are the primary cause of this error. In some magnetometers, such as the vapor magnetometers (caesium, potassium, etc.), there are sources of heading error in the physics that
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Airborne
Magnetometers detect the change in the Earth's magnetic field using sensors attached to the aircraft in the form of a "stinger" or by towing a magnetometer on the end of a cable. The magnetometer on a cable is often referred to as a "bomb" because of its shape. Others call it a "bird".
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The caesium and potassium magnetometers are typically used where a higher performance magnetometer than the proton magnetometer is needed. In archaeology and geophysics, where the sensor sweeps through an area and many accurate magnetic field measurements are often needed, caesium and potassium
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Inductive pickup coils (also referred as inductive sensor) measure the magnetic dipole moment of a material by detecting the current induced in a coil due to the changing magnetic moment of the sample. The sample's magnetization can be changed by applying a small ac magnetic field (or a rapidly
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SQUIDs are a type of magnetometer used both as survey and as laboratory magnetometers. SQUID magnetometry is an extremely sensitive absolute magnetometry technique. However SQUIDs are noise sensitive, making them impractical as laboratory magnetometers in high DC magnetic fields, and in pulsed
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The best survey results are achieved on the ground in high-resolution surveys (with approximately 10 m line spacing and 0.5 m station spacing). Bore-hole magnetometers using a
Ferretcan also assist when coal seams are deep, by using multiple sills or looking beneath surface basalt flows.
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Magnetometers are used to measure or monitor mechanical stress in ferromagnetic materials. Mechanical stress will improve alignment of magnetic domains in microscopic scale that will raise the magnetic field measured close to the material by magnetometers. There are different hypothesis about
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Pulsed-field extraction magnetometry is another method making use of pickup coils to measure magnetization. Unlike VSMs where the sample is physically vibrated, in pulsed-field extraction magnetometry, the sample is secured and the external magnetic field is changed rapidly, for example in a
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hats are very popular in
Australia, but their steel rims must be removed before use on magnetic surveys. Steel rings on notepads, steel capped boots and steel springs in overall eyelets can all cause unnecessary noise in surveys. Pens, mobile phones and stainless steel implants can also be
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There are many challenges interpreting magnetic data for mineral exploration. Multiple targets mix together like multiple heat sources and, unlike light, there is no magnetic telescope to focus fields. The combination of multiple sources is measured at the surface. The geometry, depth, or
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variability in time of the Earth's magnetic field and for other sources of electromagnetic interference, thus allowing for more sensitive detection of anomalies. Because nearly equal values are being subtracted, the noise performance requirements for the magnetometers is more extreme.
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are popular due to their compact configuration and relatively low cost. Gradiometers enhance shallow features and negate the need for a base station. Caesium and
Overhauser magnetometers are also very effective when used as gradiometers or as single-sensor systems with base stations.
1243:) to operate, hence the packaging requirements to use them are rather stringent both from a thermal-mechanical as well as magnetic standpoint. SQUID magnetometers are most commonly used to measure the magnetic fields produced by laboratory samples, also for brain or heart activity (
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between different types of magnetic orders that occur at critical temperatures or magnetic fields. This type of magnetometry measurement is very important to understand the magnetic properties of materials in physics, chemistry, geophysics and geology, as well as sometimes biology.
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new state, the electrons once again can absorb a photon of light. This causes a signal on a photo detector that measures the light passing through the cell. The associated electronics use this fact to create a signal exactly at the frequency that corresponds to the external field.
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result of a uniform magnetic field B, τ = μ × B. A torque is thus a measure of the sample's magnetic or shape anisotropy. In some cases the sample's magnetization can be extracted from the measured torque. In other cases, the magnetic torque measurement is used to detect magnetic
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capacitor-driven magnet. One of multiple techniques must then be used to cancel out the external field from the field produced by the sample. These include counterwound coils that cancel the external uniform field and background measurements with the sample removed from the coil.
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Where targets are shallow (<200 m), aeromag anomalies may be followed up with ground magnetic surveys on 10 m to 50 m line spacing with 1 m station spacing to provide the best detail (2 to 10 m pixel grid) (or 25 times the resolution prior to drilling).
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Vector magnetometers are subject to temperature drift and the dimensional instability of the ferrite cores. They also require leveling to obtain component information, unlike total field (scalar) instruments. For these reasons they are no longer used for mineral exploration.
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Console noise comes from magnetic components on or within the console. These include ferrite in cores in inductors and transformers, steel frames around LCDs, legs on IC chips and steel cases in disposable batteries. Some popular MIL spec connectors also have steel springs.
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The caesium and potassium magnetometer's faster measurement rate allows the sensor to be moved through the area more quickly for a given number of data points. Caesium and potassium magnetometers are insensitive to rotation of the sensor while the measurement is being made.
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Potassium is the only optically pumped magnetometer that operates on a single, narrow electron spin resonance (ESR) line in contrast to other alkali vapour magnetometers that use irregular, composite and wide spectral lines and helium with the inherently wide spectral line.
677:, or MOKE. In this technique, incident light is directed at the sample's surface. Light interacts with a magnetized surface nonlinearly so the reflected light has an elliptical polarization, which is then measured by a detector. Another method of optical magnetometry is
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Magnetometers can also be classified as "AC" if they measure fields that vary relatively rapidly in time (>100 Hz), and "DC" if they measure fields that vary only slowly (quasi-static) or are static. AC magnetometers find use in electromagnetic systems (such as
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The magnetic response (noise) from ferrous object on the operator and console can change with heading direction because of induction and remanence. Aeromagnetic survey aircraft and quad bike systems can use special compensators to correct for heading error noise.
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In traditional mineral exploration and archaeological work, grid pegs placed by theodolite and tape measure were used to define the survey area. Some UXO surveys used ropes to define the lanes. Airborne surveys used radio triangulation beacons, such as
Siledus.
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1973:(UXO) location. It is twice as efficient to run a base station and use two (or more) mobile sensors to read parallel lines simultaneously (assuming data is stored and post-processed). In this manner, both along-line and cross-line gradients can be calculated.
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technology to automatically record the magnetic field and their location. The data set is then corrected with data from a second magnetometer (the base station) that is left stationary and records the change in the Earth's magnetic field during the survey.
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cases, the feedback current varies linearly with the external magnetic field and is used as the basis for measurement. This helps to counter inherent non-linearity between the applied external field strength and the flux gated through the sense winding.
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are magnetometers that measure in units of gauss or tesla, respectively. In some contexts, magnetometer is the term used for an instrument that measures fields of less than 1 millitesla (mT) and gaussmeter is used for those measuring greater than 1 mT.
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There are additional factors that affect the size of the resultant signal. These factors include the number of turns in the sense winding, magnetic permeability of the core, sensor geometry, and the gated flux rate of change with respect to time.
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They are relatively inexpensive (< US$ 8,000) and were once widely used in mineral exploration. Three manufacturers dominate the market: GEM Systems, Geometrics and Scintrex. Popular models include G-856/857, Smartmag, GSM-18, and GSM-19T.
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portable units), and faster sampling as the electron-proton coupling can happen even as measurements are being taken. An Overhauser magnetometer produces readings with a 0.01 nT to 0.02 nT standard deviation while sampling once per second.
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signals. Several startup companies are currently developing optically pumped magnetometers for biomedical applications: those of TwinLeaf, quSpin and FieldLine being based on alkali vapors, and those of Mag4Health on metastable helium-4.
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Portable instruments are also limited by sensor volume (weight) and power consumption. PPMs work in field gradients up to 3,000 nT/m, which is adequate for most mineral exploration work. For higher gradient tolerance, such as mapping
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target). One analogy to the resolution-with-distance is a car driving at night with lights on. At a distance of 400 m one sees one glowing haze, but as it approaches, two headlights, and then the left blinker, are visible.
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Magnetometric surveys can be useful in defining magnetic anomalies which represent ore (direct detection), or in some cases gangue minerals associated with ore deposits (indirect or inferential detection). This includes
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For hand/backpack carried units, PPM sample rates are typically limited to less than one sample per second. Measurements are typically taken with the sensor held at fixed locations at approximately 10 metre increments.
450:, head of the Geomagnetic Observatory in Göttingen, published a paper on measurement of the Earth's magnetic field. It described a new instrument that consisted of a permanent bar magnet suspended horizontally from a
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signal seen at the photo detector. Again, the associated electronics use this to create a signal exactly at the frequency that corresponds to the external field. Both methods lead to high performance magnetometers.
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are commonly used either in a single axis or a three axis configuration. For demanding applications a high homogeneity magnetic field is mandatory, in such cases magnetic field calibration can be performed using a
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A fluxgate magnetometer consists of a small magnetically susceptible core wrapped by two coils of wire. An alternating electric current is passed through one coil, driving the core through an alternating cycle of
992:. The latter pioneered a configuration which cancels the dead-zones, which are a recurrent problem of atomic magnetometers. This configuration was demonstrated to show an accuracy of 50 pT in orbit operation. The
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vapor operate similarly to the caesium magnetometers described above, yet can reach sensitivities lower than 1 fT Hz. The SERF magnetometers only operate in small magnetic fields. The Earth's field is about 50
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is the angular region of magnetometer orientation in which the instrument produces poor or no measurements. All optically pumped, proton-free precession, and Overhauser magnetometers experience some dead zone
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sensors. These sensors produce a voltage proportional to the applied magnetic field and also sense polarity. They are used in applications where the magnetic field strength is relatively large, such as in
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They are also rated as "absolute" if the strength of the field can be calibrated from their own known internal constants or "relative" if they need to be calibrated by reference to a known field.
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is the smallest change in a magnetic field the magnetometer can resolve. A magnetometer should have a resolution a good deal smaller than the smallest change one wishes to observe. This includes
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may produce a magnetic sensor that has all of its input and output signals in the form of light on fiber-optic cables. This lets the magnetic measurement be made near high electrical voltages.
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For mineral exploration, they have been superseded by Overhauser, caesium, and potassium instruments, all of which are fast-cycling, and do not require the operator to pause between readings.
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fibre. The difference in the oscillations when the bar was magnetised and when it was demagnetised allowed Gauss to calculate an absolute value for the strength of the Earth's magnetic field.
1251:, respectively). Geophysical surveys use SQUIDs from time to time, but the logistics of cooling the SQUID are much more complicated than other magnetometers that operate at room temperature.
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The typical fluxgate magnetometer consists of a "sense" (secondary) coil surrounding an inner "drive" (primary) coil that is closely wound around a highly permeable core material, such as
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are popular, and even water can be used), causing some of the protons to align themselves with that field. The current is then interrupted, and as protons realign themselves with the
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Magnetometers such as the German Foerster are used to locate ferrous ordnance. Caesium and Overhauser magnetometers are used to locate and help clean up old bombing and test ranges.
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Magnetometers based on atomic gasses can perform vector measurements of the magnetic field in the low field regime, where the decay of the atomic coherence becomes faster than the
1825:. Their interaction framework, called MagiTact, tracks changes to the magnetic field around a cellphone to identify different gestures made by a hand holding or wearing a magnet.
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Léger, Jean-Michel; Jager, Thomas; Bertrand, François; Hulot, Gauthier; Brocco, Laura; Vigneron, Pierre; Lalanne, Xavier; Chulliat, Arnaud; Fratter, Isabelle (25 April 2015).
791:(NMR). Because the precession frequency depends only on atomic constants and the strength of the ambient magnetic field, the accuracy of this type of magnetometer can reach 1
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Magnetometers are used extensively in experimental particle physics to measure the magnetic field of pivotal components such as the concentration or focusing beam-magnets.
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becomes visible. A grid of magnetometers around the world constantly measures the effect of the solar wind on the Earth's magnetic field, which is then published on the
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For defensive purposes, navies use arrays of magnetometers laid across sea floors in strategic locations (i.e. around ports) to monitor submarine activity. The Russian
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at a frequency that is directly proportional to the magnetic field. This produces a weak rotating magnetic field that is picked up by a (sometimes separate) inductor,
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Non-magnetic electronic hipchain triggers were developed to trigger magnetometers. They used rotary shaft encoders to measure distance along disposable cotton reels.
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measure the magnitude of the vector magnetic field. Magnetometers used to study the Earth's magnetic field may express the vector components of the field in terms of
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While magnetometers can be used to help map basin shape at a regional scale, they are more commonly used to map hazards to coal mining, such as basaltic intrusions (
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1775:) and, more commonly, indirectly, such as by mapping geological structures conducive to mineralisation (i.e., shear zones and alteration haloes around granites).
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Coleman Jr., P.J.; Davis Jr., L.; Smith, E.J.; Sonett, C.P. (1962). "The Mission of Mariner II: Preliminary Observations – Interplanetary Magnetic Fields".
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Gradiometers enhance shallow magnetic anomalies and are thus good for archaeological and site investigation work. They are also good for real-time work such as
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set by sample rate. Modern magnetometers may perform smoothing or averaging over sequential samples, achieving a lower noise in exchange for lower bandwidth.
1000:, which was launched in 2013. An experimental vector mode, which could compete with fluxgate magnetometers was tested in this mission with overall success.
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electronically, and fed to a digital frequency counter whose output is typically scaled and displayed directly as field strength or output as digital data.
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in seconds per reading. Sample rate is important in mobile magnetometers; the sample rate and the vehicle speed determine the distance between measurements.
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The Magnetometer Navigation (MAGNAV) algorithm was initially running as a flight experiment in 2004. Later on, diamond magnetometers were developed by the
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556:, etc.). Measuring the magnetization as a function of temperature and magnetic field can give clues as to the type of magnetic ordering, as well as any
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Magnetic surveys can suffer from noise coming from a range of sources. Different magnetometer technologies suffer different kinds of noise problems.
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is a highly sensitive (300 fT/Hz) and accurate device used in a wide range of applications. It is one of a number of alkali vapours (including
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The lower noise of caesium and potassium magnetometers allow those measurements to more accurately show the variations in the field with position.
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Optical magnetometry makes use of various optical techniques to measure magnetization. One such technique, Kerr magnetometry makes use of the
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Operators must take care to be magnetically clean and should check the 'magnetic hygiene' of all apparel and items carried during a survey.
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magnets. Commercial SQUID magnetometers are available for sample temperatures between 300 mK and 400 K, and magnetic fields up to 7 tesla.
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measure the absolute magnitude or vector magnetic field, using an internal calibration or known physical constants of the magnetic sensor.
1608:) that destroy resources and are dangerous to longwall mining equipment. Magnetometers can also locate zones ignited by lightning and map
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Leger, Jean-Michel; Bertrand, François; Jager, Thomas; Le Prado, Matthieu; Fratter, Isabelle; Lalaurie, Jean-Claude (1 September 2009).
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Magnetometers have a very diverse range of applications, including locating objects such as submarines, sunken ships, hazards affecting
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Snare, Robert C. (1998). "A history of vector magnetometry in space". In Pfaff, Robert F.; Borovsky, Josep E.; Young, David T. (eds.).
1267:. Such zero-field optically pumped magnetometers have been tested in various configurations and with different atomic species, notably
60:. Different types of magnetometers measure the direction, strength, or relative change of a magnetic field at a particular location. A
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consumption makes them ideal for a variety of sensing applications. Gradiometers are commonly used for archaeological prospecting and
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The performance and capabilities of magnetometers are described through their technical specifications. Major specifications include
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Kominis, I.K.; Kornack, T.W.; Allred, J.C.; Romalis, M.V. (4 February 2003). "A subfemtotesla multichannel atomic magnetometer".
721:
A vector is a mathematical entity with both magnitude and direction. The Earth's magnetic field at a given point is a vector. A
328:
is the dependence of the measurement on temperature. It is given as a temperature coefficient in units of nT per degree Celsius.
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3733:
Julie Thienel; Rick Harman; Itzhack Bar-Itzhack (2004). "Results of the Magnetometer Navigation (MAGNAV) Inflight Experiment".
2296:
1667:—by passing through large underwater loops at regular intervals—to help them escape detection by sea-floor monitoring systems,
3180:
Kitching, J.; Knappe, S.; Shah, V.; Schwindt, P.; Griffith, C.; Jimenez, R.; Preusser, J.; Liew, L. -A.; Moreland, J. (2008).
1758:
magnetisation direction (remanence) of the targets are also generally not known, and so multiple models can explain the data.
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The fluxgate magnetometer was invented by H. Aschenbrenner and G. Goubau in 1936. A team at Gulf Research Laboratories led by
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Systematic surveys can be used to in searching for mineral deposits or locating lost objects. Such surveys are divided into:
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17:
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Hrvoic I (2008) Development of a new high sensitivity Potassium magnetometer for geophysical mapping, First Break 26:81–85
5750:
5709:
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3652:
3227:"The magnetic field homogeneity of coils by means of the space harmonics suppression of the current density distribution"
1837:
geologic features that make drilling impractical, and other features that give geophysicists a more complete picture of
1660:
titanium submarines were designed and built at great expense to thwart such systems (as pure titanium is non-magnetic).
4835:
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Wilson, John W.; Tian, Gui Yun; Barrans, Simon (April 2007). "Residual magnetic field sensing for stress measurement".
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is a leading magnetic (and gravity) interpretation package used extensively in the Australian exploration industry.
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orbiter for Juno can be seen here on the end of a boom. The spacecraft uses two fluxgate magnetometers. (see also
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quantities characterized by both strength and direction. The strength of a magnetic field is measured in units of
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excited to its metastable triplet state thanks to a plasma discharge have been developed in the 1960s and 70s by
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At sufficiently high atomic density, extremely high sensitivity can be achieved. Spin-exchange-relaxation-free (
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is a magnetometer that continuously records data over time. This data is typically represented in magnetograms.
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characterizes how well a magnetometer tracks rapid changes in magnetic field. For magnetometers with no onboard
79:
The first magnetometer capable of measuring the absolute magnetic intensity at a point in space was invented by
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1807:
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of the angle between the rotation axis of the coil and the field lines. This type of magnetometer is obsolete.
1045:. The amplitude of the signal is proportional to the strength of the field, provided it is uniform, and to the
936:
The basic principle that allows the device to operate is the fact that a caesium atom can exist in any of nine
392:
is the change in the measurement due to a change in orientation of the instrument in a constant magnetic field.
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713:
have the capability to measure the component of the magnetic field in a particular direction, relative to the
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5394:
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2153:
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can be exploited to significantly improve upon the proton precession magnetometer. Rather than aligning the
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2131:
1945:
On the base of space measured distribution of magnetic field parameters (e.g. amplitude or direction), the
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is the random fluctuations generated by the magnetometer sensor or electronics. Noise is given in units of
4800:
4555:
4412:
3270:
3226:
2491:"The Beginnings of Continuous Scientific Recording using Photography: Sir Francis Ronalds' Contribution"
218:(the angle between the horizontal component of the field vector and true, or geographic, north) and the
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4881:
4786:
2136:
1119:
788:
755:), and DC magnetometers are used for detecting mineralisation and corresponding geological structures.
259:
are used to measure magnetic fields in geomagnetic surveys; they may be fixed base stations, as in the
126:
3708:
2614:
1762:
1678:
Fluxgates can also be used in weapons navigation systems, but have been largely superseded by GPS and
406:
is the ability of a magnetometer to obtain a reliable measurement in the presence of a magnetic field
232:
measure magnitude or vector magnetic field relative to a fixed but uncalibrated baseline. Also called
5735:
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3644:
2757:"In-flight performance of the Absolute Scalar Magnetometer vector mode on board the Swarm satellites"
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2098:
1988:
Modern explorers use a range of low-magnetic signature GPS units, including real-time kinematic GPS.
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674:
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independently invented magnetographs in 1846 that continuously recorded the magnet's movements using
255:
are used to measure the magnetic field of materials placed within them and are typically stationary.
251:
are meant to be used while in motion and may be manually carried or transported in a moving vehicle.
121:
In recent years, magnetometers have been miniaturized to the extent that they can be incorporated in
65:
3303:
Staples, S. G. H.; Vo, C.; Cowell, D. M. J.; Freear, S.; Ives, C.; Varcoe, B. T. H. (7 April 2013).
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2822:
499:
and others in a global magnetic survey and updated machines were in use well into the 20th century.
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is one such device, one that measures the direction of an ambient magnetic field, in this case, the
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images may be generated. Such presentation of magnetic data is very useful for further analyse and
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measure the total strength of the magnetic field to which they are subjected, but not its direction
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to control the spin of rubidium atoms which can be used to measure and monitor the magnetic field.
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243:
are installed to a fixed position and measurements are taken while the magnetometer is stationary.
1903:
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4018:
2931:"High-Sensitivity Low-Noise Miniature Fluxgate Magnetometers Using a Flip Chip Conceptual Design"
1888:
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2077: – Surveying method, analyzing the magnetic properties of large regions from high altitudes
1937:
Data can be divided in point located and image data, the latter of which is in ERMapper format.
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Magnetometers assist mineral explorers both directly (i.e., gold mineralisation associated with
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1697:
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57:
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sensors are required to measure the components of the magnetic field in all three dimensions.
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of various types, and to determine the dipole moment of magnetic materials. In an aircraft's
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Earthquake forecasting techniques and more research on the study of electromagnetic fields
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1877:
and fluxgate magnetometers. Magnetometers were also a component instrument on the Mercury
1713:, modified for aerial survey with a nose-mounted boom containing a magnetometer at its tip
68:. Other magnetometers measure the magnetic dipole moment of a magnetic material such as a
8:
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Practical guidelines for building a magnetometer by hobbyists – Part 1 Introduction
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emitter, such as a laser, an absorption chamber containing caesium vapour mixed with a "
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which is caused by recording roundoff and truncation of digital expressions of the data.
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Depending on the application, magnetometers can be deployed in spacecraft, aeroplanes (
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A wide variety of sensors are currently available and used to measure magnetic fields.
1111:
1058:
997:
307:
122:
91:
1810:(MEMS) magnetometers which are used to detect magnetic field strength and are used as
1745:
Magnetic fields from magnetic bodies of ore fall off with the inverse distance cubed (
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UAV payloads also include magnetometers for a range of defensive and offensive tasks.
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2929:
Lu, Chih-Cheng; Huang, Jeff; Chiu, Po-Kai; Chiu, Shih-Liang; Jeng, Jen-Tzong (2014).
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3885:
Practical guidelines for building a magnetometer by hobbyists – Part 2 Building
3626:
3211:
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2798:
2256:"Commercial magnetometers and their application", in the book "Optical Magnetometry"
2225:
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2566:"MicroMicrofabricated Optically Pumped Magnetometers to Detect Source of Seizures"
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4908:
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4394:
4094:
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2732:
2716:"Swarm Absolute Scalar and Vector Magnetometer Based on Helium 4 Optical Pumping"
2715:
2086:
1772:
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73:
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2095: – Device for measuring or maintaining the orientation and angular velocity
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4008:
3790:
Signals from the Subatomic World: How to Build a Proton Precession Magnetometer
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pass, and a photon detector, arranged in that order. The buffer gas is usually
470:
111:
53:
3696:
3374:
3193:
2781:
2756:
2384:. Warsaw: International Association of Geomagnetism and Aeronomy. p. 51.
2107: – global network of observatories, monitoring the Earth's magnetic field
5729:
5490:
5422:
5297:
5021:
4903:
4160:
3339:
3282:
2790:
2741:
2490:
2414:"The Intensity of the Earth's Magnetic Force Reduced to Absolute Measurement"
2125:
2068:
2058:(AFRL) as a better method of navigation which cannot be jammed by the enemy.
1946:
1800:
1641:
1605:
733:
measures both the magnitude and direction of the total magnetic field. Three
541:
533:
508:
316:
is the difference between the readings of a magnetometer true magnetic field.
297:
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3254:
2252:
1290:
5655:
5481:
5417:
5016:
4948:
4110:
3732:
3618:
3105:
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1838:
1707:
1439:, or other parameter. This helps to reveal its magnetic properties such as
1341:
1319:
1268:
1264:
1157:
by using them to measure shifts in the magnetic patterns on the sea floor.
1150:
937:
874:
545:
529:
474:
458:
236:, relative magnetometers are used to measure variations in magnetic field.
155:
147:
125:
at very low cost and are finding increasing use as miniaturized compasses (
90:
Magnetometers are widely used for measuring the Earth's magnetic field, in
32:
815:
3020:
2910:"Victor Vacquier Sr. dies at 101; geophysicist was a master of magnetics"
2116: – Instrument for detecting variations in the Earth's magnetic field
2104:
1999:
Heading errors are one group of noise. They can come from three sources:
1962:
1950:
1645:
1550:
1432:
1173:
1106:
1067:
933:
and they are used to reduce collisions between the caesium vapour atoms.
637:
525:
524:, among others. Ordering of magnetic moments are primarily classified as
260:
239:
Magnetometers may also be classified by their situation or intended use.
84:
69:
3742:
3141:
3097:
2144: – Electronic instrument which detects the presence of metal nearby
1075:
in cars, which sense wheel rotation speed via slots in the wheel disks.
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5167:
5160:
5026:
4998:
4675:
4668:
4646:
4568:
4337:
4220:
4190:
4143:
4136:
4104:
3610:
3224:
2955:
1863:
1821:
have used magnetometers embedded in mobile devices to permit touchless
1731:
1664:
1568:. Ploughed fields behave as sources of magnetic noise in such surveys.
1475:
1386: in this section. Unsourced material may be challenged and removed.
918:
819:
734:
641:
633:
553:
159:
41:
37:
3665:
3420:
Aeromagnetic Survey in Afghanistan: A Website for Distribution of Data
3331:
1640:
of the drilling tools near the drill. They are most often paired with
1149:
developed airborne fluxgate magnetometers to detect submarines during
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5683:
5521:
5427:
5283:
5272:
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5262:
5181:
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3993:
3422:(Report). United States Geological Survey. OF 07-1247. Archived from
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2092:
1879:
1857:
1768:
1723:
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1452:
1306:
1193:
1090:
907:
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unpaired electrons within its atoms, with smaller contributions from
3926:
3181:
3034:
2441:
1576:
Magnetometers can give an indication of auroral activity before the
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423:
5607:
5600:
5469:
5125:
4688:
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4233:
4166:
4154:
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2850:. Washington, D. C.: American Geophysical Union. pp. 101–114.
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2374:
1727:
1719:
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1314:
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941:
930:
903:
807:
803:
799:
495:, thus easing the load on observers. They were quickly utilised by
407:
263:
network, or mobile magnetometers used to scan a geographic region.
2641:
Requirements for obtaining high accuracy with proton magnetometers
955:
change and therefore measure the magnitude of the magnetic field.
83:
in 1833 and notable developments in the 19th century included the
5399:
5136:
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4652:
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4622:
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1833:
1811:
1637:
1585:
1310:
897:
478:
440:
222:(the angle between the field vector and the horizontal surface).
184:
151:
115:
61:
3666:
Dougherty M.K.; Kellock S.; Southwood D.J.; et al. (2004).
3305:"Solving the inverse problem of magnetisation–stress resolution"
2593:"Measuring Field Strength with an Optically Pumped Magnetometer"
2128: – Physical quantity, density of magnetic moment per volume
5629:
5257:
5252:
5154:
4953:
4561:
4542:
4332:
4285:
4240:
4062:
3973:
3968:
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3852:
2022:
1746:
1581:
1272:
1231:
1225:
926:
922:
914:
882:
811:
787:(hydrogen nuclei) in the magnetic field to be measured, due to
784:
629:
549:
278:
is the number of readings given per second. The inverse is the
2815:
Applications of Magnetoresistive Sensors in Navigation Systems
4920:
4856:
4362:
3767:"Magnetometers based on diamonds will make navigation easier"
2378:
IAGA GUIDE FOR MAGNETIC MEASUREMENTS AND OISERVAIORY PRACTICE
2226:"USGS FS–236–95: Introduction to Potential Fields: Magnetics"
2147:
1577:
1218:
1213:
570:
3048:
3000:"Landmine and UXO detection brochure – Foerster Instruments"
2689:
2156: – scientific instrument to measure magnetic properties
1883:
mission. A magnetometer can also be used by satellites like
1254:
1009:
magnetometers have advantages over the proton magnetometer.
4741:
4367:
4045:
3857:
3648:
3075:
2253:
D. C. Hovde; M. D. Prouty; I. Hrvoic; R. E. Slocum (2013).
1907:
Ground surveying in Surprise Valley, Cedarville, California
1302:
1296:
1280:
1046:
451:
3503:(1st ed.). Sebastopol, CA: O'Reilly. pp. 57–70.
3225:
Coillot, C.; Nativel, E.; Zanca, M.; Goze-Bac, C. (2016).
3179:
3127:
Budker, D.; Romalis, M.V. (2006). "Optical Magnetometry".
2713:
2351:
2037:
in survey images. Alternate lines can also be corrugated.
1930:
Aeromag datasets for Australia can be downloaded from the
1523:
Aust.-Synchrotron,-Quadrupole-Magnets-of-Linac,-14.06.2007
975:
783:, PPMs or simply mags, measure the resonance frequency of
694:
Survey magnetometers can be divided into two basic types:
2352:
Tauxe, L.; Banerjee, S.K.; Butler, R.F.; van der Voo, R.
1423:
Magnetometers can measure the magnetic fields of planets.
1322:; SERF magnetometers operate in fields less than 0.5 μT.
1291:
Spin-exchange relaxation-free (SERF) atomic magnetometers
940:, which can be informally thought of as the placement of
540:(although the zoology of magnetic ordering also includes
462:
3735:
AIAA/AAS Astrodynamics Specialist Conference and Exhibit
1873:
mission to explore Saturn. This system is composed of a
1702:
1344:, cosine coils, or calibration in the highly homogenous
1025:
total magnetic intensity, TMI) can be calculated by the
988:, then by its spinoff Polatomic, and from late 1980s by
3182:"Microfabricated atomic magnetometers and applications"
2754:
1976:
1867:
missions. A dual technique magnetometer is part of the
605:
200:
There are two basic types of magnetometer measurement.
2354:"Essentials of Paleomagnetism: Third Web Edition 2014"
2046:
is also a hard copy and need for systematic coverage.
1181:(UXO) detection such as the German military's popular
594:
3499:
Allan, Alasdair (2011). "5. Using the magnetometer".
3302:
2517:
Sir Francis Ronalds: Father of the Electric Telegraph
2014:
contribute small amounts to the total heading error.
1991:
1041:
The magnetic field induces a sine wave in a rotating
340:
2540:
David Gubbins; Emilio Herrero-Bervera, eds. (2007).
2158:
Pages displaying wikidata descriptions as a fallback
2109:
Pages displaying wikidata descriptions as a fallback
2089: – Measurement of ambient electromagnetic field
2040:
1263:. The physics of such magnetometers is based on the
380:, where frequency component refers to the bandwidth.
3186:
2008 IEEE International Frequency Control Symposium
2722:. Proceedings of the Eurosensors XXIII conference.
2375:JERZY JANKOWSKI & CHRISTIAN SUCKSDORFF (1996).
2122: – Diagnostic immunoassay using magnetic beads
1855:A three-axis fluxgate magnetometer was part of the
839:
565:
SQUID (superconducting quantum interference device)
204:measure the vector components of a magnetic field.
2907:
1549:, and other buried or submerged objects. Fluxgate
372:
3417:
3352:
2868:: CS1 maint: DOI inactive as of September 2024 (
856:
763:
5727:
3927:Science instruments on satellites and spacecraft
2595:. National Institute of Standards and Technology
2259:. Cambridge University Press. pp. 387–405.
2071: – Device that measures proper acceleration
1619:Modern surveys generally use magnetometers with
1505:
1224:SQUID magnetometers require cooling with liquid
966:
843:
163:of 100 nT, and magnetic field variations due to
3830:. Boca Raton, FL: CRC Press. pp. 159–256.
3523:
2928:
2542:Encyclopedia of Geomagnetism and Paleomagnetism
2495:European Society for the History of Photography
2290:
2288:
2183:
2181:
2179:
2165: – Acquisition of NMR spectra of chemicals
2101: – Accelerometer-based navigational device
1329:
373:{\displaystyle {\rm {{nT}/{\sqrt {\rm {Hz}}}}}}
266:
3572:
2848:Measurement Techniques in Space Plasmas Fields
1749:target), or at best inverse distance squared (
889:
72:, for example by recording the effect of this
3912:
3551:. Portal.acm.org. Retrieved on 23 March 2011.
3418:Abraham, Jared D.; et al. (April 2008).
3126:
2811:
1063:The most common magnetic sensing devices are
1036:
655:
644:and nearby fixed object, or by measuring the
435:Coast and Geodetic Survey Magnetometer No. 18
427:The compass is a simple type of magnetometer.
386:is the larger of the noise or the resolution.
3826:Tumanski, S. (2011). "4. Magnetic sensors".
3787:
2285:
2176:
2655:"A History of Vector Magnetometry in Space"
2652:
2411:
2248:
2246:
2056:United States Air Force Research Laboratory
1895:of the magnetic field of a planet or moon.
1141:Basic principles of a fluxgate magnetometer
1078:
1052:
502:
3919:
3905:
3668:"The Cassini magnetic field investigation"
2356:. Magnetics Information Consortium (MagIC)
1153:and after the war confirmed the theory of
628:. The most common way to measure magnetic
322:is the change in absolute error over time.
3253:
3140:
2964:
2954:
2885:Fluxgate Magnetometers for Space Research
2780:
2731:
2558:
2294:
1761:Potent by Geophysical Software Solutions
1402:Learn how and when to remove this message
1255:Zero-field optically-pumped magnetometers
802:creates a strong magnetic field around a
579:
4198:
3825:
3788:Hollos, Stefan; Hollos, Richard (2008).
3641:"Cassini Orbiter Instruments – MAG"
2345:
2243:
2218:
2083: – NMR use in the geomagnetic field
1902:
1790:
1701:
1518:
1413:
1130:
1118:
1110:
1100:
869:uses the same fundamental effect as the
469:was named in his honour, defined as one
430:
422:
183:
179:
36:Helium vector magnetometer (HVM) of the
31:
2882:
2514:
2488:
2368:
1648:and azimuth of the drill can be found.
1627:
1019:
976:Metastable helium-4 scalar magnetometer
758:
689:
668:
14:
5728:
5214:
3268:
2908:Thomas H. Maugh II (24 January 2009).
2590:
2584:
2049:
1806:Many smartphones contain miniaturized
1691:
1541:Magnetometers are also used to detect
1514:
614:
473:per square centimeter; it equals 1×10
418:
3900:
3806:
3498:
3443:
3441:
3234:Journal of Sensors and Sensor Systems
2845:
2643:". GEM Systems Inc., 11 January 2010.
2187:
1335:feature. For this reason, coils like
1207:
838:and detecting large ferrous objects,
507:Laboratory magnetometers measure the
414:or landfills, gradients can be large.
100:attitude and heading reference system
1977:Position control of magnetic surveys
1795:Tri-axis Electronic Magnetometer by
1384:adding citations to reliable sources
1355:
606:Pulsed-field extraction magnetometry
188:The Magnetometer experiment for the
167:can be in the picotesla (pT) range.
5710:Venetia Burney Student Dust Counter
2901:
1898:
1644:in drilling tools so that both the
1591:
652:off the surface of the cantilever.
595:VSM (vibrating-sample magnetometer)
24:
3809:Magnetic sensors and magnetometers
3780:
3474:"The application of titanium Navy"
3438:
3271:"What are magnetometers, or mags?"
3021:"MicroSERF Twinleaf magnetometers"
2519:. London: Imperial College Press.
1992:Heading errors in magnetic surveys
1874:
1828:
1451:, or other properties that affect
1305:) atomic magnetometers containing
1271:(potassium, rubidium and cesium),
362:
359:
347:
344:
137:
76:on the induced current in a coil.
25:
5767:
3846:
3828:Handbook of magnetic measurements
3524:Willie D. Jones (February 2010),
3355:Sensors and Actuators A: Physical
2041:Image processing of magnetic data
1089:These are made of thin strips of
913:The device broadly consists of a
725:is designed to give a horizontal
636:and measure the displacement via
296:, bandwidth is determined by the
114:: they can detect only magnetic (
3449:"GMW Associates - Oil & Gas"
3395:. 1 October 2007. Archived from
2988:http://www.ti.com/lit/gpn/drv425
2887:. Norderstedt: Books on Demand.
2821:, Honeywell Inc., archived from
2639:Dr. Ivan Hrvoic, Ph.D., P.Eng. "
1940:
1786:
1360:
1115:A uniaxial fluxgate magnetometer
873:to take measurements. By adding
5679:International Lunar Observatory
4490:(TRMM, Terra, Aura, Suomi NPP,
3811:. Boston, Mass.: Artech House.
3759:
3726:
3659:
3633:
3554:
3542:
3526:"A Compass in Every Smartphone"
3517:
3492:
3466:
3411:
3393:Space Weather Prediction Center
3381:
3346:
3296:
3262:
3218:
3173:
3120:
3069:
3055:
3041:
3027:
3013:
2992:
2981:
2922:
2876:
2839:
2805:
2748:
2707:
2682:
2673:
2646:
2633:
2607:
2533:
2508:
2482:
2199:. CRC Press LLC. Archived from
1371:needs additional citations for
1003:
132:
3269:Javaid, Maham (29 June 2022).
2456:
2430:
2405:
2324:10.1088/0953-8984/19/16/165217
1956:
1808:microelectromechanical systems
1530:
1474:), towed at a distance behind
996:chose this technology for the
877:to the measurement fluid, the
871:proton precession magnetometer
863:Overhauser effect magnetometer
857:Overhauser effect magnetometer
798:A direct current flowing in a
775:Proton precession magnetometer
764:Proton precession magnetometer
600:Vibrating-sample magnetometers
102:, they are commonly used as a
87:, which is still widely used.
27:Device that measures magnetism
13:
1:
5625:High Resolution Stereo Camera
3603:10.1126/science.138.3545.1099
2591:Kelley, Sean (26 July 2016).
2170:
2154:Vibrating-sample magnetometer
1844:
1636:for oil or gas to detect the
1537:Magnetic survey (archaeology)
1506:Mechanical stress measurement
1462:magnetometers), helicopters (
967:Potassium vapour magnetometer
910:) that are used in this way.
679:Faraday rotation magnetometry
110:Magnetometers can be used as
2883:Musmann, Günter Dr. (2010).
2858:(inactive 6 September 2024).
2733:10.1016/j.proche.2009.07.158
2440:. CT Systems. Archived from
2190:"Magnetic field measurement"
2150: – Type of magnetometer
2132:Magnetogram (disambiguation)
1330:Calibration of magnetometers
921:" through which the emitted
842:can handle 10,000 nT/m, and
632:is to mount the sample on a
267:Performance and capabilities
7:
5312:
4556:Radiation Budget Instrument
3035:"quSpin QZFM magnetometers"
2621:. British Geological Survey
2438:"Magnetometer: The History"
2061:
1651:
1486:), lowered into boreholes (
890:Caesium vapour magnetometer
10:
5772:
5751:Nuclear magnetic resonance
4882:Infrared Space Observatory
3807:Ripka, Pavel, ed. (2001).
3312:Journal of Applied Physics
2856:10.1002/9781118664391.ch12
2297:"Advances in magnetometry"
2137:MEMS magnetic field sensor
1848:
1695:
1669:magnetic anomaly detectors
1632:Magnetometers are used in
1571:
1534:
1498:), or towed behind boats (
1294:
1211:
1104:
1082:
1056:
1037:Rotating coil magnetometer
789:nuclear magnetic resonance
767:
656:Faraday force magnetometry
583:
568:
127:MEMS magnetic field sensor
52:is a device that measures
5692:
5669:
5648:
5617:
5586:
5551:
5542:
5462:
5452:
5410:
5378:
5371:
5362:
5336:
5320:
5311:
5238:
5222:
5213:
5147:
5113:
5104:
5062:
5053:
4980:
4971:
4849:
4808:
4799:
4779:
4772:
4765:
4727:
4720:
4592:
4446:
4439:
4386:
4207:
4189:
4017:
3932:
3868:Space-based magnetometers
3863:Earth's Field NMR (EFNMR)
3858:USGS Geomagnetism Program
3697:10.1007/s11214-004-1432-2
3375:10.1016/j.sna.2006.08.010
3194:10.1109/FREQ.2008.4623107
2782:10.1186/s40623-015-0231-1
2464:"Ferromagnetic Materials"
2304:J. Phys.: Condens. Matter
2114:Magnetic anomaly detector
2099:Inertial measurement unit
2033:Heading errors look like
1675:sonar node in the array.
1073:anti-lock braking systems
879:nuclear Overhauser effect
675:magneto-optic Kerr effect
648:of the cantilever, or by
206:Total field magnetometers
5705:Inertial Stellar Compass
5070:Raman Laser Spectrometer
3890:24 February 2021 at the
2761:Earth, Planets and Space
2295:Edelstein, Alan (2007).
1663:Military submarines are
1079:Magnetoresistive devices
1053:Hall effect magnetometer
846:can handle 30,000 nT/m.
840:Overhauser magnetometers
640:measurement between the
518:nuclear magnetic moments
503:Laboratory magnetometers
253:Laboratory magnetometers
241:Stationary magnetometers
5700:Deep Space Atomic Clock
4959:Venus Emissivity Mapper
3318:(13): 133905–133905–6.
3255:10.5194/jsss-5-401-2016
2773:2015EP&S...67...57L
1851:Spacecraft magnetometer
1612:(an impurity in coal).
1351:
980:Magnetometers based on
867:Overhauser magnetometer
3792:. Abrazol Publishing.
2515:Ronalds, B.F. (2016).
2489:Ronalds, B.F. (2016).
1908:
1803:
1714:
1698:Exploration geophysics
1564:clays, such as on the
1524:
1429:tunnel boring machines
1424:
1346:Earth's magnetic field
1245:magnetoencephalography
1142:
1128:
1116:
836:banded iron formations
650:optical interferometry
580:Inductive pickup coils
436:
428:
374:
230:Relative magnetometers
226:Absolute magnetometers
197:
66:Earth's magnetic field
58:magnetic dipole moment
45:
5746:Measuring instruments
5715:Plasma Wave Subsystem
4826:Multispectral Scanner
4150:Pioneer Venus Orbiter
3954:Pioneer Venus Orbiter
3676:Space Science Reviews
3568:on 11 September 2018.
2915:The Los Angeles Times
2690:"Polatomic - Welcome"
2310:(16): 165217 (28pp).
2188:Macintyre, Steven A.
1906:
1794:
1705:
1680:ring laser gyroscopes
1566:Great Hungarian Plain
1522:
1422:
1140:
1122:
1114:
1101:Fluxgate magnetometer
1095:magnetic permeability
844:caesium magnetometers
818:magnetic field, they
729:direction, whereas a
663:dilution refrigerator
467:magnetic flux density
434:
426:
375:
187:
180:Types of magnetometer
35:
18:Fluxgate magnetometer
4683:Mars Climate Orbiter
4325:RM-08 and MTVZA-OK (
3878:10 July 2012 at the
3501:Basic sensors in iOS
3063:"Mag4Health website"
2444:on 30 September 2007
2412:Gauss, C.F. (1832).
2120:Magnetic immunoassay
2035:herringbone patterns
1887:to measure both the
1634:directional drilling
1628:Directional drilling
1543:archaeological sites
1380:improve this article
1020:Vector magnetometers
780:proton magnetometers
759:Scalar magnetometers
690:Survey magnetometers
669:Optical magnetometry
626:quantum oscillations
511:, also known as the
448:Carl Friedrich Gauss
338:
257:Survey magnetometers
249:mobile magnetometers
210:scalar magnetometers
202:Vector magnetometers
142:Magnetic fields are
81:Carl Friedrich Gauss
5640:Mars Orbiter Camera
3743:10.2514/6.2004-4749
3689:2004SSRv..114..331D
3595:1962Sci...138.1099C
3589:(3545): 1099–1100.
3480:. 15 September 2010
3367:2007SeAcA.135..381W
3324:2013JAP...113m3905S
3246:2016JSSS....5..401C
3151:2007NatPh...3..227B
3098:10.1038/nature01484
3090:2003Natur.422..596K
3049:"FieldLine website"
2947:2014Senso..1413815L
2812:Michael J. Caruso,
2619:BGS Information Hub
2316:2007JPCM...19p5217E
2197:ENG Net Base (2000)
2075:Aeromagnetic survey
2050:Aircraft navigation
1971:unexploded ordnance
1916:Aeromagnetic survey
1692:Mineral exploration
1515:Accelerator physics
1249:magnetocardiography
1179:unexploded ordnance
1163:magnetic saturation
1027:Pythagorean theorem
900:vapour magnetometer
770:Proton magnetometer
731:vector magnetometer
715:spatial orientation
615:Torque magnetometry
522:Larmor diamagnetism
419:Early magnetometers
412:unexploded ordnance
194:Magnetometer (Juno)
123:integrated circuits
92:geophysical surveys
5618:Imagers/telescopes
4766:Spectrophotometers
3478:Free press release
3426:on 26 October 2011
3399:on 22 October 2013
3275:The New York Times
2956:10.3390/s140813815
2941:(8): 13815–13829.
2720:Procedia Chemistry
1909:
1804:
1715:
1525:
1470:), on the ground (
1445:antiferromagnetism
1425:
1208:SQUID magnetometer
1170:Fluxgate compasses
1143:
1129:
1117:
1059:Hall effect sensor
437:
429:
404:Gradient tolerance
370:
308:quantization error
198:
165:magnetic anomalies
96:magnetic anomalies
46:
5723:
5722:
5660:Rosalind Franklin
5582:
5581:
5578:
5577:
5569:Rosalind Franklin
5544:Mass spectrometer
5538:
5537:
5474:Rosalind Franklin
5448:
5447:
5358:
5357:
5354:
5353:
5307:
5306:
5215:Triaxial fluxgate
5100:
5099:
5096:
5095:
5074:Rosalind Franklin
5049:
5048:
4973:UV-visible (UVVS)
4967:
4966:
4863:Rosalind Franklin
4801:Visible-IR (VIRS)
4795:
4794:
4761:
4760:
4757:
4756:
4716:
4715:
4435:
4434:
4247:DMSP 5D-2/F13-F15
3837:978-1-4398-2952-3
3818:978-1-58053-057-6
3799:978-1-887187-09-1
3752:978-1-62410-075-8
3737:. Research Gate.
3714:on 10 August 2017
3510:978-1-4493-1542-9
3332:10.1063/1.4799049
3203:978-1-4244-1794-0
2694:www.polatomic.com
2653:Robert C. Snare.
2551:978-1-4020-3992-8
2526:978-1-78326-917-4
2391:978-0-9650686-2-8
2266:978-0-511-84638-0
2081:Earth's field NMR
1797:AKM Semiconductor
1783:recording a GPS.
1751:magnetic monopole
1449:superconductivity
1420:
1412:
1411:
1404:
1138:
1085:Magnetoresistance
986:Texas Instruments
896:optically pumped
777:s, also known as
622:phase transitions
558:phase transitions
538:antiferromagnetic
366:
326:Thermal stability
294:signal processing
16:(Redirected from
5763:
5736:Magnetic devices
5561:(Europa Clipper)
5549:
5548:
5510:(on ExoMars TGO)
5460:
5459:
5454:Neutral particle
5376:
5375:
5369:
5368:
5318:
5317:
5220:
5219:
5206:(Europa Clipper)
5111:
5110:
5060:
5059:
4978:
4977:
4806:
4805:
4777:
4776:
4770:
4769:
4725:
4724:
4721:Ultraviolet (UV)
4444:
4443:
4440:Infrared-visible
4205:
4204:
4196:
4195:
3921:
3914:
3907:
3898:
3897:
3841:
3822:
3803:
3775:
3774:
3763:
3757:
3756:
3730:
3724:
3723:
3721:
3719:
3713:
3707:. Archived from
3683:(1–4): 331–383.
3672:
3663:
3657:
3656:
3655:on 8 April 2014.
3651:. Archived from
3637:
3631:
3630:
3576:
3570:
3569:
3564:. Archived from
3558:
3552:
3546:
3540:
3539:
3538:
3536:
3521:
3515:
3514:
3496:
3490:
3489:
3487:
3485:
3470:
3464:
3463:
3461:
3459:
3445:
3436:
3435:
3433:
3431:
3415:
3409:
3408:
3406:
3404:
3385:
3379:
3378:
3350:
3344:
3343:
3309:
3300:
3294:
3293:
3291:
3289:
3266:
3260:
3259:
3257:
3231:
3222:
3216:
3215:
3177:
3171:
3170:
3159:10.1038/nphys566
3144:
3124:
3118:
3117:
3073:
3067:
3066:
3059:
3053:
3052:
3045:
3039:
3038:
3031:
3025:
3024:
3017:
3011:
3010:
3008:
3006:
2996:
2990:
2985:
2979:
2978:
2968:
2958:
2926:
2920:
2919:
2905:
2899:
2898:
2880:
2874:
2873:
2867:
2859:
2843:
2837:
2836:
2835:
2833:
2827:
2820:
2809:
2803:
2802:
2784:
2752:
2746:
2745:
2735:
2711:
2705:
2704:
2702:
2700:
2686:
2680:
2677:
2671:
2670:
2668:
2666:
2657:. Archived from
2650:
2644:
2637:
2631:
2630:
2628:
2626:
2611:
2605:
2604:
2602:
2600:
2588:
2582:
2581:
2579:
2577:
2562:
2556:
2555:
2537:
2531:
2530:
2512:
2506:
2505:
2503:
2501:
2486:
2480:
2479:
2477:
2475:
2466:. Archived from
2460:
2454:
2453:
2451:
2449:
2434:
2428:
2427:
2425:
2423:
2418:
2409:
2403:
2402:
2401:on 4 March 2016.
2400:
2394:. Archived from
2383:
2372:
2366:
2365:
2363:
2361:
2349:
2343:
2342:
2340:
2338:
2301:
2292:
2283:
2282:
2280:
2278:
2269:. Archived from
2250:
2241:
2240:
2238:
2236:
2230:
2222:
2216:
2215:
2213:
2211:
2206:on 19 March 2015
2205:
2194:
2185:
2159:
2110:
1899:Magnetic surveys
1819:Deutsche Telekom
1773:kimberlite pipes
1592:Coal exploration
1421:
1407:
1400:
1396:
1393:
1387:
1364:
1356:
1261:Larmor frequency
1242:
1234:
1139:
1125:fluxgate compass
753:magnetotellurics
723:magnetic compass
646:piezoelectricity
586:Inductive sensor
410:. In surveys of
379:
377:
376:
371:
369:
368:
367:
365:
357:
355:
350:
21:
5771:
5770:
5766:
5765:
5764:
5762:
5761:
5760:
5726:
5725:
5724:
5719:
5688:
5671:
5665:
5644:
5613:
5574:
5534:
5444:
5406:
5364:
5350:
5345:Cassini–Huygens
5332:
5303:
5247:Cassini–Huygens
5234:
5209:
5143:
5092:
5045:
4993:Mariner 6 and 7
4963:
4909:Mariner 6 and 7
4845:
4791:
4773:Long wavelength
4753:
4712:
4641:Mariner 6 and 7
4588:
4517:MESSR and VTIR
4431:
4401:Electra (radio)
4395:Cassini-Huygens
4382:
4185:
4035:Cassini–Huygens
4013:
3941:Cassini–Huygens
3928:
3925:
3892:Wayback Machine
3880:Wayback Machine
3849:
3844:
3838:
3819:
3800:
3783:
3781:Further reading
3778:
3773:. 18 July 2020.
3765:
3764:
3760:
3753:
3731:
3727:
3717:
3715:
3711:
3670:
3664:
3660:
3639:
3638:
3634:
3577:
3573:
3560:
3559:
3555:
3547:
3543:
3534:
3532:
3522:
3518:
3511:
3497:
3493:
3483:
3481:
3472:
3471:
3467:
3457:
3455:
3447:
3446:
3439:
3429:
3427:
3416:
3412:
3402:
3400:
3387:
3386:
3382:
3351:
3347:
3307:
3301:
3297:
3287:
3285:
3267:
3263:
3229:
3223:
3219:
3204:
3188:. p. 789.
3178:
3174:
3142:physics/0611246
3125:
3121:
3084:(6932): 596–9.
3074:
3070:
3061:
3060:
3056:
3047:
3046:
3042:
3033:
3032:
3028:
3019:
3018:
3014:
3004:
3002:
2998:
2997:
2993:
2986:
2982:
2927:
2923:
2906:
2902:
2895:
2881:
2877:
2861:
2860:
2844:
2840:
2831:
2829:
2825:
2818:
2810:
2806:
2753:
2749:
2712:
2708:
2698:
2696:
2688:
2687:
2683:
2678:
2674:
2664:
2662:
2651:
2647:
2638:
2634:
2624:
2622:
2613:
2612:
2608:
2598:
2596:
2589:
2585:
2575:
2573:
2572:. 17 April 2017
2564:
2563:
2559:
2552:
2538:
2534:
2527:
2513:
2509:
2499:
2497:
2487:
2483:
2473:
2471:
2470:on 27 June 2015
2462:
2461:
2457:
2447:
2445:
2436:
2435:
2431:
2421:
2419:
2416:
2410:
2406:
2398:
2392:
2381:
2373:
2369:
2359:
2357:
2350:
2346:
2336:
2334:
2299:
2293:
2286:
2276:
2274:
2273:on 7 April 2014
2267:
2251:
2244:
2234:
2232:
2228:
2224:
2223:
2219:
2209:
2207:
2203:
2192:
2186:
2177:
2173:
2168:
2157:
2108:
2087:EMF measurement
2064:
2052:
2043:
1994:
1979:
1959:
1943:
1901:
1870:Cassini–Huygens
1853:
1847:
1831:
1829:Oil exploration
1817:Researchers at
1789:
1700:
1694:
1654:
1630:
1594:
1574:
1557:The TV program
1539:
1533:
1517:
1508:
1414:
1408:
1397:
1391:
1388:
1377:
1365:
1354:
1337:Helmholtz coils
1332:
1299:
1293:
1257:
1240:
1237:liquid nitrogen
1229:
1216:
1210:
1155:plate tectonics
1147:Victor Vacquier
1131:
1109:
1103:
1087:
1081:
1061:
1055:
1039:
1022:
1006:
978:
969:
945:atomic orbitals
892:
859:
772:
766:
761:
692:
683:Meissner effect
671:
658:
617:
608:
597:
588:
582:
573:
567:
513:magnetic moment
505:
485:Francis Ronalds
421:
358:
356:
351:
343:
342:
341:
339:
336:
335:
269:
182:
140:
138:Magnetic fields
135:
112:metal detectors
74:magnetic dipole
28:
23:
22:
15:
12:
11:
5:
5769:
5759:
5758:
5753:
5748:
5743:
5738:
5721:
5720:
5718:
5717:
5712:
5707:
5702:
5696:
5694:
5690:
5689:
5687:
5686:
5681:
5675:
5673:
5667:
5666:
5664:
5663:
5652:
5650:
5646:
5645:
5643:
5642:
5637:
5632:
5627:
5621:
5619:
5615:
5614:
5612:
5611:
5604:
5597:
5590:
5588:
5584:
5583:
5580:
5579:
5576:
5575:
5573:
5572:
5562:
5555:
5553:
5552:Interplanetary
5546:
5540:
5539:
5536:
5535:
5533:
5532:
5525:
5518:
5511:
5505:
5495:
5486:
5477:
5466:
5464:
5463:Interplanetary
5457:
5450:
5449:
5446:
5445:
5443:
5442:
5435:
5430:
5425:
5420:
5414:
5412:
5411:Interplanetary
5408:
5407:
5405:
5404:
5403:
5402:
5388:
5382:
5380:
5373:
5366:
5360:
5359:
5356:
5355:
5352:
5351:
5349:
5348:
5340:
5338:
5337:Interplanetary
5334:
5333:
5331:
5330:
5324:
5322:
5315:
5309:
5308:
5305:
5304:
5302:
5301:
5294:
5287:
5280:
5275:
5270:
5265:
5260:
5255:
5250:
5242:
5240:
5239:Interplanetary
5236:
5235:
5233:
5232:
5226:
5224:
5217:
5211:
5210:
5208:
5207:
5197:
5185:
5178:
5171:
5164:
5157:
5151:
5149:
5148:Interplanetary
5145:
5144:
5142:
5141:
5140:
5139:
5129:
5123:
5117:
5115:
5108:
5102:
5101:
5098:
5097:
5094:
5093:
5091:
5090:
5077:
5066:
5064:
5063:Interplanetary
5057:
5051:
5050:
5047:
5046:
5044:
5043:
5036:
5029:
5024:
5019:
5014:
5009:
5002:
4995:
4990:
4984:
4982:
4981:Interplanetary
4975:
4969:
4968:
4965:
4964:
4962:
4961:
4956:
4951:
4946:
4941:
4938:Europa Clipper
4923:
4918:
4911:
4906:
4901:
4895:
4884:
4879:
4878:
4877:
4872:
4859:
4853:
4851:
4850:Interplanetary
4847:
4846:
4844:
4843:
4838:
4833:
4828:
4823:
4818:
4812:
4810:
4803:
4797:
4796:
4793:
4792:
4790:
4789:
4783:
4781:
4780:Interplanetary
4774:
4767:
4763:
4762:
4759:
4758:
4755:
4754:
4752:
4751:
4750:
4749:
4739:
4731:
4729:
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4718:
4717:
4714:
4713:
4711:
4710:
4703:
4696:
4691:
4686:
4679:
4672:
4665:
4660:
4655:
4650:
4643:
4638:
4633:
4627:
4626:
4616:
4606:
4596:
4594:
4593:Interplanetary
4590:
4589:
4587:
4586:
4572:
4565:
4558:
4553:
4546:
4539:
4533:
4528:
4527:
4526:
4523:
4515:
4512:
4505:
4500:
4495:
4485:
4480:
4475:
4470:
4456:
4450:
4448:
4441:
4437:
4436:
4433:
4432:
4430:
4429:
4422:
4410:
4403:
4398:
4390:
4388:
4387:Interplanetary
4384:
4383:
4381:
4380:
4375:
4370:
4365:
4360:
4355:
4350:
4345:
4340:
4335:
4330:
4323:
4318:
4317:
4316:
4313:
4307:
4300:
4293:
4279:
4274:
4269:
4264:
4259:
4254:
4249:
4244:
4237:
4230:
4224:
4217:
4211:
4209:
4202:
4193:
4187:
4186:
4184:
4183:
4176:
4169:
4164:
4157:
4152:
4147:
4140:
4133:
4128:
4121:
4114:
4107:
4102:
4097:
4092:
4087:
4082:
4077:
4072:
4065:
4060:
4055:
4048:
4046:ExoMars lander
4043:
4038:
4031:
4023:
4021:
4015:
4014:
4012:
4011:
4006:
4001:
3996:
3991:
3986:
3981:
3976:
3971:
3966:
3961:
3956:
3951:
3944:
3936:
3934:
3930:
3929:
3924:
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3916:
3909:
3901:
3895:
3894:
3882:
3870:
3865:
3860:
3855:
3848:
3847:External links
3845:
3843:
3842:
3836:
3823:
3817:
3804:
3798:
3784:
3782:
3779:
3777:
3776:
3758:
3751:
3725:
3658:
3632:
3571:
3553:
3541:
3516:
3509:
3491:
3465:
3453:GMW Associates
3437:
3410:
3380:
3361:(2): 381–387.
3345:
3295:
3261:
3240:(2): 401–408.
3217:
3202:
3172:
3135:(4): 227–234.
3129:Nature Physics
3119:
3068:
3054:
3040:
3026:
3012:
2991:
2980:
2921:
2900:
2893:
2875:
2838:
2828:on 5 July 2010
2804:
2747:
2726:(1): 634–637.
2706:
2681:
2672:
2661:on 20 May 2012
2645:
2632:
2615:"Magnetograms"
2606:
2583:
2557:
2550:
2532:
2525:
2507:
2481:
2455:
2429:
2404:
2390:
2367:
2344:
2284:
2265:
2242:
2217:
2174:
2172:
2169:
2167:
2166:
2163:Zero field NMR
2160:
2151:
2145:
2142:Metal detector
2139:
2134:
2129:
2123:
2117:
2111:
2102:
2096:
2090:
2084:
2078:
2072:
2065:
2063:
2060:
2051:
2048:
2042:
2039:
2011:
2010:
2007:
2004:
1993:
1990:
1978:
1975:
1958:
1955:
1942:
1939:
1932:GADDS database
1928:
1927:
1924:
1921:
1918:
1900:
1897:
1849:Main article:
1846:
1843:
1830:
1827:
1823:3D interaction
1788:
1785:
1771:, diamonds in
1711:light aircraft
1696:Main article:
1693:
1690:
1653:
1650:
1642:accelerometers
1629:
1626:
1593:
1590:
1573:
1570:
1535:Main article:
1532:
1529:
1516:
1513:
1507:
1504:
1441:ferromagnetism
1437:magnetic field
1410:
1409:
1392:September 2024
1368:
1366:
1359:
1353:
1350:
1331:
1328:
1295:Main article:
1292:
1289:
1256:
1253:
1212:Main article:
1209:
1206:
1102:
1099:
1083:Main article:
1080:
1077:
1057:Main article:
1054:
1051:
1038:
1035:
1021:
1018:
1005:
1002:
977:
974:
968:
965:
949:atomic nucleus
891:
888:
858:
855:
768:Main article:
765:
762:
760:
757:
719:
718:
717:of the device.
705:
691:
688:
670:
667:
657:
654:
616:
613:
607:
604:
596:
593:
584:Main article:
581:
578:
569:Main article:
566:
563:
504:
501:
489:Charles Brooke
420:
417:
416:
415:
401:
393:
387:
381:
364:
361:
354:
349:
346:
329:
323:
317:
314:Absolute error
311:
301:
283:
268:
265:
181:
178:
139:
136:
134:
131:
54:magnetic field
26:
9:
6:
4:
3:
2:
5768:
5757:
5754:
5752:
5749:
5747:
5744:
5742:
5741:Magnetometers
5739:
5737:
5734:
5733:
5731:
5716:
5713:
5711:
5708:
5706:
5703:
5701:
5698:
5697:
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5691:
5685:
5682:
5680:
5677:
5676:
5674:
5668:
5661:
5657:
5654:
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5651:
5647:
5641:
5638:
5636:
5633:
5631:
5628:
5626:
5623:
5622:
5620:
5616:
5610:
5609:
5605:
5603:
5602:
5598:
5595:
5592:
5591:
5589:
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5570:
5566:
5563:
5560:
5557:
5556:
5554:
5550:
5547:
5545:
5541:
5531:
5530:
5526:
5523:
5519:
5517:
5516:
5512:
5509:
5506:
5503:
5499:
5496:
5493:
5492:
5491:Venus Express
5488:ASPERA-4 (on
5487:
5484:
5483:
5479:ASPERA-3 (on
5478:
5475:
5471:
5468:
5467:
5465:
5461:
5458:
5455:
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5421:
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5416:
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5413:
5409:
5401:
5398:
5397:
5396:
5392:
5389:
5387:
5384:
5383:
5381:
5377:
5374:
5372:Ion detectors
5370:
5367:
5361:
5347:
5346:
5342:
5341:
5339:
5335:
5329:
5326:
5325:
5323:
5319:
5316:
5314:
5310:
5300:
5299:
5298:Venus Express
5295:
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5281:
5279:
5276:
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5146:
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5000:
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4544:
4540:
4538:(Terra, Aqua)
4537:
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4280:
4278:
4275:
4273:
4270:
4268:
4265:
4263:
4260:
4258:
4255:
4253:
4252:DMSP 5D-2/F16
4250:
4248:
4245:
4242:
4238:
4235:
4231:
4228:
4225:
4222:
4218:
4216:
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4161:Venus Express
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4049:
4047:
4044:
4042:
4039:
4037:
4036:
4032:
4030:
4029:
4025:
4024:
4022:
4020:
4019:Radio science
4016:
4010:
4007:
4005:
4002:
4000:
3997:
3995:
3992:
3990:
3987:
3985:
3982:
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3899:
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3889:
3886:
3883:
3881:
3877:
3874:
3871:
3869:
3866:
3864:
3861:
3859:
3856:
3854:
3851:
3850:
3839:
3833:
3829:
3824:
3820:
3814:
3810:
3805:
3801:
3795:
3791:
3786:
3785:
3772:
3771:The Economist
3768:
3762:
3754:
3748:
3744:
3740:
3736:
3729:
3710:
3706:
3702:
3698:
3694:
3690:
3686:
3682:
3678:
3677:
3669:
3662:
3654:
3650:
3646:
3642:
3636:
3628:
3624:
3620:
3616:
3612:
3608:
3604:
3600:
3596:
3592:
3588:
3584:
3583:
3575:
3567:
3563:
3557:
3550:
3545:
3531:
3530:IEEE Spectrum
3527:
3520:
3512:
3506:
3502:
3495:
3479:
3475:
3469:
3454:
3450:
3444:
3442:
3425:
3421:
3414:
3398:
3394:
3390:
3389:"The K-index"
3384:
3376:
3372:
3368:
3364:
3360:
3356:
3349:
3341:
3337:
3333:
3329:
3325:
3321:
3317:
3313:
3306:
3299:
3284:
3280:
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3265:
3256:
3251:
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3134:
3130:
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3115:
3111:
3107:
3103:
3099:
3095:
3091:
3087:
3083:
3079:
3072:
3064:
3058:
3050:
3044:
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3030:
3022:
3016:
3001:
2995:
2989:
2984:
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2972:
2967:
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2952:
2948:
2944:
2940:
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2925:
2917:
2916:
2911:
2904:
2896:
2894:9783839137024
2890:
2886:
2879:
2871:
2865:
2857:
2853:
2849:
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2817:
2816:
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2800:
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2202:
2198:
2191:
2184:
2182:
2180:
2175:
2164:
2161:
2155:
2152:
2149:
2146:
2143:
2140:
2138:
2135:
2133:
2130:
2127:
2126:Magnetization
2124:
2121:
2118:
2115:
2112:
2106:
2103:
2100:
2097:
2094:
2091:
2088:
2085:
2082:
2079:
2076:
2073:
2070:
2069:Accelerometer
2067:
2066:
2059:
2057:
2047:
2038:
2036:
2031:
2027:
2026:problematic.
2024:
2019:
2015:
2008:
2005:
2002:
2001:
2000:
1997:
1989:
1986:
1983:
1974:
1972:
1967:
1964:
1954:
1952:
1948:
1947:magnetovision
1941:Magnetovision
1938:
1935:
1933:
1925:
1922:
1919:
1917:
1914:
1913:
1912:
1905:
1896:
1894:
1890:
1886:
1882:
1881:
1876:
1875:vector helium
1872:
1871:
1866:
1865:
1860:
1859:
1852:
1842:
1840:
1835:
1826:
1824:
1820:
1815:
1813:
1809:
1802:
1801:Motorola Xoom
1798:
1793:
1787:Mobile phones
1784:
1780:
1776:
1774:
1770:
1765:
1763:
1759:
1755:
1752:
1748:
1743:
1739:
1735:
1733:
1729:
1725:
1721:
1712:
1709:
1704:
1699:
1689:
1686:
1683:
1681:
1676:
1672:
1670:
1666:
1661:
1659:
1649:
1647:
1643:
1639:
1635:
1625:
1622:
1617:
1613:
1611:
1607:
1606:volcanic plug
1603:
1599:
1589:
1587:
1583:
1579:
1569:
1567:
1562:
1561:
1555:
1552:
1548:
1544:
1538:
1528:
1521:
1512:
1503:
1501:
1497:
1493:
1489:
1485:
1481:
1478:(ATVs) on a (
1477:
1473:
1469:
1465:
1461:
1456:
1454:
1450:
1446:
1442:
1438:
1434:
1430:
1406:
1403:
1395:
1385:
1381:
1375:
1374:
1369:This section
1367:
1363:
1358:
1357:
1349:
1347:
1343:
1338:
1327:
1323:
1321:
1316:
1312:
1308:
1304:
1298:
1288:
1284:
1282:
1278:
1274:
1270:
1266:
1262:
1252:
1250:
1246:
1238:
1233:
1227:
1222:
1220:
1215:
1205:
1201:
1197:
1195:
1191:
1186:
1184:
1180:
1175:
1171:
1166:
1164:
1158:
1156:
1152:
1148:
1127:/inclinometer
1126:
1121:
1113:
1108:
1098:
1096:
1092:
1086:
1076:
1074:
1069:
1066:
1060:
1050:
1048:
1044:
1034:
1030:
1028:
1017:
1014:
1010:
1001:
999:
998:Swarm mission
995:
991:
987:
983:
973:
964:
960:
956:
952:
950:
946:
943:
939:
938:energy levels
934:
932:
928:
924:
920:
916:
911:
909:
905:
901:
899:
887:
884:
880:
876:
875:free radicals
872:
868:
864:
854:
851:
847:
845:
841:
837:
831:
827:
825:
821:
817:
813:
809:
806:-rich fluid (
805:
801:
796:
794:
790:
786:
782:
781:
776:
771:
756:
754:
748:
746:
741:
738:
736:
732:
728:
724:
716:
712:
711:magnetometers
710:
706:
703:
702:magnetometers
701:
697:
696:
695:
687:
684:
680:
676:
666:
664:
653:
651:
647:
643:
639:
635:
631:
627:
623:
612:
603:
601:
592:
587:
577:
572:
562:
559:
555:
551:
547:
543:
542:ferrimagnetic
539:
535:
534:ferromagnetic
531:
527:
523:
519:
514:
510:
509:magnetization
500:
498:
497:Edward Sabine
494:
490:
486:
482:
480:
476:
472:
468:
464:
460:
455:
453:
449:
444:
442:
433:
425:
413:
409:
405:
402:
398:
394:
391:
390:Heading error
388:
385:
382:
352:
333:
330:
327:
324:
321:
318:
315:
312:
309:
305:
302:
299:
298:Nyquist limit
295:
291:
287:
284:
281:
277:
274:
273:
272:
264:
262:
258:
254:
250:
246:
242:
237:
235:
231:
227:
223:
221:
217:
216:
211:
207:
203:
195:
191:
186:
177:
174:
170:
166:
161:
157:
153:
149:
145:
130:
128:
124:
119:
117:
113:
108:
105:
101:
97:
93:
88:
86:
82:
77:
75:
71:
67:
63:
59:
55:
51:
43:
39:
34:
30:
19:
5670:Astronomical
5659:
5656:MicrOmega-IR
5606:
5599:
5596:(on InSight)
5587:Seismometers
5568:
5527:
5513:
5501:
5489:
5482:Mars Express
5480:
5473:
5437:
5343:
5313:Helium vapor
5296:
5289:
5282:
5245:
5191:
5180:
5173:
5166:
5159:
5106:Magnetometer
5105:
5085:Perseverance
5084:
5073:
5038:
5031:
5004:
4997:
4913:
4891:
4887:
4862:
4705:
4698:
4674:
4667:
4645:
4602:Schiaparelli
4600:
4599:COMARS+ (on
4514:Kanopus-V-IK
4424:
4416:
4405:
4393:
4178:
4171:
4159:
4142:
4135:
4123:
4116:
4111:Mars Express
4109:
4067:
4050:
4033:
4026:
3946:
3939:
3827:
3808:
3789:
3770:
3761:
3734:
3728:
3716:. Retrieved
3709:the original
3680:
3674:
3661:
3653:the original
3635:
3586:
3580:
3574:
3566:the original
3556:
3544:
3533:, retrieved
3529:
3519:
3500:
3494:
3482:. Retrieved
3477:
3468:
3456:. Retrieved
3452:
3428:. Retrieved
3424:the original
3413:
3401:. Retrieved
3397:the original
3383:
3358:
3354:
3348:
3315:
3311:
3298:
3286:. Retrieved
3274:
3264:
3237:
3233:
3220:
3185:
3175:
3132:
3128:
3122:
3081:
3077:
3071:
3057:
3043:
3029:
3015:
3003:. Retrieved
2994:
2983:
2938:
2934:
2924:
2913:
2903:
2884:
2878:
2847:
2841:
2830:, retrieved
2823:the original
2814:
2807:
2764:
2760:
2750:
2723:
2719:
2709:
2697:. Retrieved
2693:
2684:
2675:
2663:. Retrieved
2659:the original
2648:
2635:
2623:. Retrieved
2618:
2609:
2597:. Retrieved
2586:
2574:. Retrieved
2569:
2560:
2544:. Springer.
2541:
2535:
2516:
2510:
2498:. Retrieved
2494:
2484:
2472:. Retrieved
2468:the original
2458:
2446:. Retrieved
2442:the original
2432:
2420:. Retrieved
2407:
2396:the original
2377:
2370:
2358:. Retrieved
2347:
2335:. Retrieved
2307:
2303:
2275:. Retrieved
2271:the original
2255:
2233:. Retrieved
2220:
2208:. Retrieved
2201:the original
2196:
2053:
2044:
2032:
2028:
2020:
2016:
2012:
1998:
1995:
1987:
1984:
1980:
1968:
1963:gradiometers
1960:
1944:
1936:
1929:
1910:
1878:
1868:
1862:
1856:
1854:
1839:stratigraphy
1832:
1816:
1805:
1781:
1777:
1766:
1760:
1756:
1744:
1740:
1736:
1730:, and often
1716:
1708:Diamond DA42
1687:
1684:
1677:
1673:
1662:
1655:
1631:
1618:
1614:
1595:
1575:
1558:
1556:
1551:gradiometers
1540:
1526:
1509:
1499:
1495:
1491:
1487:
1483:
1479:
1471:
1467:
1463:
1459:
1457:
1426:
1398:
1389:
1378:Please help
1373:verification
1370:
1342:Maxwell coil
1333:
1324:
1300:
1285:
1265:Hanle effect
1258:
1223:
1217:
1202:
1198:
1187:
1182:
1174:gradiometers
1167:
1159:
1151:World War II
1144:
1088:
1062:
1040:
1031:
1023:
1015:
1011:
1007:
1004:Applications
979:
970:
961:
957:
953:
935:
912:
895:
893:
870:
866:
862:
860:
852:
848:
832:
828:
797:
778:
774:
773:
749:
745:magnetograph
744:
742:
739:
730:
720:
707:
698:
693:
672:
659:
618:
609:
598:
589:
574:
546:helimagnetic
530:paramagnetic
506:
483:
456:
445:
438:
403:
396:
389:
383:
331:
325:
319:
313:
303:
289:
285:
279:
275:
270:
256:
252:
248:
244:
240:
238:
233:
229:
225:
224:
219:
214:
209:
205:
201:
199:
172:
168:
141:
133:Introduction
120:
109:
94:, to detect
89:
78:
50:magnetometer
49:
47:
29:
5672:instruments
5649:Microscopes
4315:Meteor-M2-1
4304:Meteor-3M-1
2105:Intermagnet
1957:Gradiometer
1951:data fusion
1646:inclination
1531:Archaeology
1433:temperature
1281:SERF effect
1107:Gradiometer
1068:Hall effect
1065:solid-state
947:around the
638:capacitance
526:diamagnetic
493:photography
384:Sensitivity
276:Sample rate
261:INTERMAGNET
234:variometers
220:inclination
215:declination
173:teslameters
169:Gaussmeters
85:Hall effect
70:ferromagnet
5730:Categories
5379:Near-Earth
5321:Near-Earth
5291:Pioneer 11
5223:Near-Earth
5161:Pioneer 10
5114:Near-Earth
4999:Mariner 10
4809:Near-Earth
4728:Near-Earth
4681:PMIRR (on
4669:Pioneer 10
4647:Mariner 10
4569:Sentinel-3
4447:Near-Earth
4338:Sentinel-3
4309:MTVZA-GYa
4272:Kanopus-ST
4221:Sentinel-6
4208:Near-Earth
4191:Radiometer
4041:Europa-UVS
3718:1 November
3562:"中国科技论文在线"
3535:21 October
3484:9 December
3403:21 October
3005:25 October
2832:21 October
2665:25 October
2625:5 December
2448:21 October
2422:21 October
2171:References
1864:Mariner 10
1845:Spacecraft
1732:pyrrhotite
1658:Alfa-class
1547:shipwrecks
1476:quad bikes
1460:fixed wing
1105:See also:
919:buffer gas
735:orthogonal
642:cantilever
634:cantilever
554:spin glass
304:Resolution
280:cycle time
160:cgs system
44:spacecraft
38:Pioneer 10
5684:MoonLIGHT
5522:Mariner 2
5502:Curiosity
5428:Mariner 2
5365:detectors
5284:MESSENGER
5263:Mariner 2
5175:Voyager 1
5033:Voyager 1
5006:MESSENGER
4915:MESSENGER
4900:(on Juno)
4888:Voyager 1
4831:SCIAMACHY
4700:Voyager 1
4663:2M No.522
4658:2M No.521
4579:Suomi NPP
4407:Mariner 2
4312:Meteor-M2
4299:, MOS-1b)
4200:Microwave
4173:Voyager 1
4131:Pioneer 7
4118:MESSENGER
4075:Mariner 2
3430:25 August
3340:0021-8979
3283:0362-4331
2864:cite book
2791:1880-5981
2767:(1): 57.
2742:1876-6196
2570:Medgadget
2332:108531365
2093:Gyroscope
1961:Magnetic
1893:direction
1889:magnitude
1880:MESSENGER
1858:Mariner 2
1812:compasses
1799:, inside
1769:magnetite
1724:magnetite
1665:degaussed
1580:from the
1560:Time Team
1453:magnetism
1307:potassium
1241:77 K
1230:4.2
1194:permalloy
1093:, a high
1091:Permalloy
908:potassium
824:amplified
446:In 1833,
397:dead zone
286:Bandwidth
154:, and in
5601:Viking 1
5520:SPS (on
5470:ADRON-RM
5456:detector
5423:ASPERA-4
5418:ASPERA-3
5363:Particle
5126:QuakeSat
4926:E-THEMIS
4689:Venera 9
4531:Meteor-2
4509:ADEOS II
4321:Nimbus 7
4267:GPM Core
4234:ADEOS II
4167:Venera 9
4155:Sakigake
4069:Magellan
4028:Akatsuki
3979:Venera 4
3948:Magellan
3888:Archived
3876:Archived
3627:19708490
3619:17772967
3549:MagiTact
3458:16 March
3288:7 August
3212:46471890
3167:96446612
3106:12686995
2975:25196107
2799:55990684
2599:18 April
2576:18 April
2360:30 March
2337:29 March
2277:30 March
2235:29 March
2210:29 March
2062:See also
2009:Operator
1920:Borehole
1728:hematite
1720:iron ore
1652:Military
1610:siderite
1500:tow fish
1472:backpack
1315:rubidium
1190:mu-metal
1183:Foerster
990:CEA-Leti
982:helium-4
942:electron
931:nitrogen
904:rubidium
808:kerosene
804:hydrogen
800:solenoid
550:toroidal
465:unit of
408:gradient
400:effects.
290:bandpass
245:Portable
152:SI units
5756:Sensors
5529:Ulysses
5439:Ulysses
5400:Proba-2
5386:DEMETER
5137:Proba-2
5128:1 and 2
5080:SHERLOC
4870:MA-MISS
4747:Proba-2
4653:Mars 96
4636:Luna 13
4623:InSight
4609:Diviner
4583:NOAA-21
4567:SLSTR (
4492:NOAA-20
4483:AVNIR-2
4426:Rosetta
4378:Zond-PP
4327:Sich-1M
4302:MTVZA (
4262:Envisat
4241:Shizuku
4239:AMSR2 (
4219:AMR-C (
4058:InSight
4052:Galileo
3705:3035894
3685:Bibcode
3611:1709490
3591:Bibcode
3582:Science
3363:Bibcode
3320:Bibcode
3242:Bibcode
3147:Bibcode
3114:4204465
3086:Bibcode
2966:4179035
2943:Bibcode
2935:Sensors
2769:Bibcode
2312:Bibcode
2006:Console
1834:Seismic
1638:azimuth
1586:K-index
1572:Auroras
1484:trailer
1464:stinger
1311:caesium
1277:mercury
923:photons
898:caesium
883:protons
820:precess
816:ambient
785:protons
727:bearing
479:SI unit
471:maxwell
441:compass
158:in the
150:in the
116:ferrous
104:heading
62:compass
5662:rover)
5630:HiRISE
5571:rover)
5559:MASPEX
5515:Nozomi
5476:rover)
5258:Magsat
5253:FIELDS
5200:ICEMAG
5155:FIELDS
5076:rover)
5022:SPICAV
5017:SPICAM
4954:SPICAV
4949:SPICAM
4886:IRIS (
4736:EURECA
4562:GCOM-C
4560:SGLI (
4550:EURECA
4543:JERS-1
4333:Seasat
4286:MOPITT
4232:AMSR (
4229:(AQUA)
4227:AMSR-E
4125:Nozomi
4063:Kaguya
4009:WISDOM
3974:MARSIS
3969:SHARAD
3964:SELENE
3959:REASON
3834:
3815:
3796:
3749:
3703:
3625:
3617:
3609:
3507:
3338:
3281:
3210:
3200:
3165:
3112:
3104:
3078:Nature
2973:
2963:
2891:
2797:
2789:
2740:
2699:11 May
2548:
2523:
2500:2 June
2474:26 May
2388:
2330:
2263:
2231:. USGS
2023:Akubra
2003:Sensor
1926:Marine
1923:Ground
1747:dipole
1604:, and
1582:aurora
1492:probe,
1273:helium
1269:alkali
1226:helium
1219:SQUIDs
927:helium
915:photon
812:decane
709:Vector
700:Scalar
630:torque
461:, the
144:vector
5635:LORRI
5508:FREND
5328:Swarm
5230:Swarm
5087:rover
5055:Raman
5012:NOMAD
4988:Alice
4944:Ralph
4921:MERIS
4898:JIRAM
4865:rover
4857:AKARI
4734:ORI (
4575:VIIRS
4548:ORI (
4541:OPS (
4536:MODIS
4521:MOS-1
4507:GLI (
4488:CERES
4478:AVNIR
4467:Terra
4459:ASTER
4454:AVHRR
4373:WSF-M
4363:SSMIS
4358:SSM/I
4297:MOS-1
4295:MSR (
4290:Terra
4277:MIRAS
3933:Radar
3712:(PDF)
3701:S2CID
3671:(PDF)
3623:S2CID
3607:JSTOR
3308:(PDF)
3230:(PDF)
3208:S2CID
3163:S2CID
3137:arXiv
3110:S2CID
2826:(PDF)
2819:(PDF)
2795:S2CID
2417:(PDF)
2399:(PDF)
2382:(PDF)
2328:S2CID
2300:(PDF)
2229:(PDF)
2204:(PDF)
2193:(PDF)
2148:SQUID
1602:sills
1598:dykes
1578:light
1496:sonde
1313:, or
1235:) or
1214:SQUID
571:SQUID
536:, or
477:(the
475:tesla
459:gauss
332:Noise
320:Drift
156:gauss
148:tesla
5693:Misc
5594:SEIS
5565:MOMA
5500:(on
5395:DSLP
5393:and
5391:TPMU
5204:PIMS
5202:and
5193:Juno
5132:SGVM
5121:GOES
4936:(on
4934:SUDA
4930:MISE
4890:and
4875:ISEM
4841:TRMM
4821:MOMS
4816:CASE
4742:LYRA
4631:IRIS
4621:(on
4611:(on
4503:ERSS
4498:ERBS
4473:AIRS
4463:MISR
4418:Juno
4368:TRMM
4353:SMOS
4348:SMMR
4343:SMAP
4282:MISR
4257:ERSS
4215:AQUA
4095:6, 7
3832:ISBN
3813:ISBN
3794:ISBN
3747:ISBN
3720:2017
3649:NASA
3615:PMID
3537:2012
3505:ISBN
3486:2013
3460:2022
3432:2011
3405:2009
3336:ISSN
3290:2024
3279:ISSN
3198:ISBN
3102:PMID
3007:2012
2971:PMID
2889:ISBN
2870:link
2834:2012
2787:ISSN
2738:ISSN
2701:2022
2667:2012
2627:2022
2601:2017
2578:2017
2546:ISBN
2521:ISBN
2502:2016
2476:2015
2450:2009
2424:2009
2386:ISBN
2362:2014
2339:2014
2279:2014
2261:ISBN
2237:2014
2212:2014
1891:and
1885:GOES
1861:and
1488:tool
1480:sled
1468:bird
1466:and
1352:Uses
1303:SERF
1297:SERF
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