2387:
most interference to the amateurs, and was happy to see them on the road to a hoped - for extinction. From the amateurs' point of view, their development of the shortwave spectrum began less as a love affair than a shotgun marriage. However, all that would change...It took several years before experimenters ventured above 2-3 mc. and started to understand such things as shortwave propagation and directionality. The short waves, as they were called, were surrounded with mystery...Also in 1928 Radio News publisher Hugo
Gernsback began shortwave broadcasting on 9700 kc. from his station, WRNY, New York, using the call W2XAL. "A reader in New South Wales, Aus- tralia," reported Gernsback, "writes us that while he was writing his letter he was listening to WRNY's short-wave transmitter, 2XAL, on a three-tube set; and had to turn down the volume, otherwise he would wake up his family. All this at a distance of some 10,000 miles! Yet 2XAL ...uses less than 500 watts; a quite negligible amount of power. "6...The 1930s were the golden age of shortwave broadcasting...Shortwave also facilitated communication with people in remote areas. Amateur radio became a basic ingredient of all expeditions...The term shortwave was generally taken to refer to anything above 1.5 mc., without upper limit...",
2185:(Another part of our theory about which doubt may arise is the assumption that the agents of terrestrial magnetic force have their source exclusively in the interior of the Earth. If the immediate causes should be sought entirely or in part outside , then we can — in so far as we exclude baseless fantasies and we want to restrict ourselves to the scientifically known — consider only galvanic currents. Atmospheric air is not a conductor of such currents; empty space also is not: thus our knowledge fails us when we seek a carrier for galvanic currents in the upper regions . Only the enigmatic phenomena of the northern lights — in which by all appearances electricity in motion plays a major role — prohibits us from simply denying the possibility of such currents just on account of that ignorance, and in any case it remains interesting to investigate how the magnetic effect resulting from would manifest itself on the Earth's surface.)
1644:. An ionosonde sweeps a range of frequencies, usually from 0.1 to 30 MHz, transmitting at vertical incidence to the ionosphere. As the frequency increases, each wave is refracted less by the ionization in the layer, and so each penetrates further before it is reflected. Eventually, a frequency is reached that enables the wave to penetrate the layer without being reflected. For ordinary mode waves, this occurs when the transmitted frequency just exceeds the peak plasma, or critical, frequency of the layer. Tracings of the reflected high frequency radio pulses are known as ionograms. Reduction rules are given in: "URSI Handbook of Ionogram Interpretation and Reduction", edited by
3581:
1548:
703:
517:
1222:. During the first half of the 20th century it was widely used for transoceanic telephone and telegraph service, and business and diplomatic communication. Due to its relative unreliability, shortwave radio communication has been mostly abandoned by the telecommunications industry, though it remains important for high-latitude communication where satellite-based radio communication is not possible. Shortwave broadcasting is useful in crossing international boundaries and covering large areas at low cost. Automated services still use
911:
3593:
599:, ionization can reach unusually high levels in the D-region over high and polar latitudes. Such very rare events are known as Polar Cap Absorption (or PCA) events, because the increased ionization significantly enhances the absorption of radio signals passing through the region. In fact, absorption levels can increase by many tens of dB during intense events, which is enough to absorb most (if not all) transpolar HF radio signal transmissions. Such events typically last less than 24 to 48 hours.
1104:(3–30 kHz) signals will be reflected by the D layer instead of the E layer, where the increased atmospheric density will usually increase the absorption of the wave and thus dampen it. As soon as the X-rays end, the sudden ionospheric disturbance (SID) or radio black-out steadily declines as the electrons in the D-region recombine rapidly and propagation gradually returns to pre-flare conditions over minutes to hours depending on the solar flare strength and frequency.
1448:
497:
31:
1607:), involve high power radio transmitters to modify the properties of the ionosphere. These investigations focus on studying the properties and behavior of ionospheric plasma, with particular emphasis on being able to understand and use it to enhance communications and surveillance systems for both civilian and military purposes. HAARP was started in 1993 as a proposed twenty-year experiment, and is currently active near Gakona, Alaska.
1028:
850:
525:
3629:
3653:
425:, in which a free electron is "captured" by a positive ion. Recombination occurs spontaneously, and causes the emission of a photon carrying away the energy produced upon recombination. As gas density increases at lower altitudes, the recombination process prevails, since the gas molecules and ions are closer together. The balance between these two processes determines the quantity of ionization present.
3605:
3641:
3617:
1010:) (100–130 km (60–80 mi) altitude). Resulting from this current is an electrostatic field directed west–east (dawn–dusk) in the equatorial day side of the ionosphere. At the magnetic dip equator, where the geomagnetic field is horizontal, this electric field results in an enhanced eastward current flow within ± 3 degrees of the magnetic equator, known as the
688:
high signal levels are often reached. The skip distances are generally around 1,640 km (1,020 mi). Distances for one hop propagation can be anywhere from 900 to 2,500 km (560 to 1,550 mi). Multi-hop propagation over 3,500 km (2,200 mi) is also common, sometimes to distances of 15,000 km (9,300 mi) or more.
2386:
Quote: "...In addition to having to obtain licenses - a constraint to which they adapted only slowly - the amateurs were, with some exceptions, restricted to the range below 200 meters (that is, above 1500 kc.), bands that were largely unexplored and thought to be of little value. The navy attributed
1610:
The SuperDARN radar project researches the high- and mid-latitudes using coherent backscatter of radio waves in the 8 to 20 MHz range. Coherent backscatter is similar to Bragg scattering in crystals and involves the constructive interference of scattering from ionospheric density irregularities.
1230:
hobbyists for private recreational contacts and to assist with emergency communications during natural disasters. Armed forces use shortwave so as to be independent of vulnerable infrastructure, including satellites, and the low latency of shortwave communications make it attractive to stock traders,
579:
are significantly attenuated within the D layer, as the passing radio waves cause electrons to move, which then collide with the neutral molecules, giving up their energy. Lower frequencies experience greater absorption because they move the electrons farther, leading to greater chance of collisions.
247:
We have in quite recent years seen the universal adoption of the term 'stratosphere'..and..the companion term 'troposphere'... The term 'ionosphere', for the region in which the main characteristic is large scale ionisation with considerable mean free paths, appears appropriate as an addition to
2350:
Speaking of wireless telegraphy, Heaviside speculated about the propagation of
Hertzian (radio) waves through the atmosphere. From p. 215: "There may possibly be a sufficiently conducting layer in the upper air. If so, the waves will, so to speak, catch on to it more or less. Then the guidance will
945:
layer daytime ion production is higher in the summer, as expected, since the Sun shines more directly on the Earth. However, there are seasonal changes in the molecular-to-atomic ratio of the neutral atmosphere that cause the summer ion loss rate to be even higher. The result is that the increase in
687:
very exciting when long-distance propagation paths that are generally unreachable "open up" to two-way communication. There are multiple causes of sporadic-E that are still being pursued by researchers. This propagation occurs every day during June and July in northern hemisphere mid-latitudes when
634:
layer can reflect frequencies up to 50 MHz and higher. The vertical structure of the E layer is primarily determined by the competing effects of ionization and recombination. At night the E layer weakens because the primary source of ionization is no longer present. After sunset an increase in
1103:
can occur that hit the sunlit side of Earth with hard X-rays. The X-rays penetrate to the D-region, releasing electrons that rapidly increase absorption, causing a high frequency (3–30 MHz) radio blackout that can persist for many hours after strong flares. During this time very low frequency
1703:
signal tangentially scrapes the Earth, passing through the atmosphere, and is received by a Low Earth Orbit (LEO) satellite. As the signal passes through the atmosphere, it is refracted, curved and delayed. An LEO satellite samples the total electron content and bending angle of many such signal
1259:
is less than unity. Hence, the electromagnetic "ray" is bent away from the normal rather than toward the normal as would be indicated when the refractive index is greater than unity. It can also be shown that the refractive index of a plasma, and hence the ionosphere, is frequency-dependent, see
1180:
In 1925, C. T. R. Wilson proposed a mechanism by which electrical discharge from lightning storms could propagate upwards from clouds to the ionosphere. Around the same time, Robert Watson-Watt, working at the Radio
Research Station in Slough, UK, suggested that the ionospheric sporadic E layer
504:
At night the F layer is the only layer of significant ionization present, while the ionization in the E and D layers is extremely low. During the day, the D and E layers become much more heavily ionized, as does the F layer, which develops an additional, weaker region of ionisation known as the
1118:
Associated with solar flares is a release of high-energy protons. These particles can hit the Earth within 15 minutes to 2 hours of the solar flare. The protons spiral around and down the magnetic field lines of the Earth and penetrate into the atmosphere near the magnetic poles increasing the
1247:
at the same frequency as the radio wave. Some of the radio-frequency energy is given up to this resonant oscillation. The oscillating electrons will then either be lost to recombination or will re-radiate the original wave energy. Total refraction can occur when the collision frequency of the
714:
or region, also known as the
Appleton–Barnett layer, extends from about 150 km (93 mi) to more than 500 km (310 mi) above the surface of Earth. It is the layer with the highest electron density, which implies signals penetrating this layer will escape into space. Electron
803:
Models are usually expressed as computer programs. The model may be based on basic physics of the interactions of the ions and electrons with the neutral atmosphere and sunlight, or it may be a statistical description based on a large number of observations or a combination of physics and
1812:, especially in older literature). The Earth's magnetic field is measured around the planet by many observatories. The data retrieved is processed and turned into measurement indices. Daily measurements for the entire planet are made available through an estimate of the
1743:
F10.7 and R12 are two indices commonly used in ionospheric modelling. Both are valuable for their long historical records covering multiple solar cycles. F10.7 is a measurement of the intensity of solar radio emissions at a frequency of 2800 MHz made using a ground
225:
and his team demonstrated the influence of sunlight on radio wave propagation, revealing that short waves became weak or inaudible while long waves steadied during the eclipse, thus contributing to the understanding of the ionosphere's role in radio transmission.
1663:
radars operate above the critical frequencies. Therefore, the technique allows probing the ionosphere, unlike ionosondes, also above the electron density peaks. The thermal fluctuations of the electron density scattering the transmitted signals lack
950:
ionization is actually lower in the local summer months. This effect is known as the winter anomaly. The anomaly is always present in the northern hemisphere, but is usually absent in the southern hemisphere during periods of low solar activity.
832:, and in situ instruments on several satellites and rockets. IRI is updated yearly. IRI is more accurate in describing the variation of the electron density from bottom of the ionosphere to the altitude of maximum density than in describing the
1214:" propagation, has been used since the 1920s to communicate at international or intercontinental distances. The returning radio waves can reflect off the Earth's surface into the sky again, allowing greater ranges to be achieved with multiple
678:
E-layer) is characterized by small, thin clouds of intense ionization, which can support reflection of radio waves, frequently up to 50 MHz and rarely up to 450 MHz. Sporadic-E events may last for just a few minutes to many hours.
584:, particularly at 10 MHz and below, with progressively less absorption at higher frequencies. This effect peaks around noon and is reduced at night due to a decrease in the D layer's thickness; only a small part remains due to
214:, limiting their operations to frequencies above 1.5 MHz (wavelength 200 meters or smaller). The government thought those frequencies were useless. This led to the discovery of HF radio propagation via the ionosphere in 1923.
2183:"§ 36. Ein anderer Theil unserer Theorie, über welchen ein Zweifel Statt finden kann, ist die Voraussetzung, … zu untersuchen, wie die aus denselben hervorgehende magnetische Wirkung auf der Erdoberfläche sich gestalten würde."
3078:
1210:) radio waves, the ionosphere can reflect radio waves directed into the sky back toward the Earth. Radio waves directed at an angle into the sky can return to Earth beyond the horizon. This technique, called "skip" or "
2180:
Gauss speculated that magnetic forces might be generated not only by electrical currents flowing through the Earth's interior but also by some sort of electrical current(s) flowing through the atmosphere. From p. 50:
1170:. These so-called "whistler" mode waves can interact with radiation belt particles and cause them to precipitate onto the ionosphere, adding ionization to the D-region. These disturbances are called "lightning-induced
1391:
626:). Normally, at oblique incidence, this layer can only reflect radio waves having frequencies lower than about 10 MHz and may contribute a bit to absorption on frequencies above. However, during intense
1751:
However, both indices are only indirect indicators of solar ultraviolet and X-ray emissions, which are primarily responsible for causing ionization in the Earth's upper atmosphere. We now have data from the
1185:) appeared to be enhanced as a result of lightning but that more work was needed. In 2005, C. Davis and C. Johnson, working at the Rutherford Appleton Laboratory in Oxfordshire, UK, demonstrated that the E
617:
is the middle layer, 90 to 150 km (56 to 93 mi) above the surface of the Earth. Ionization is due to soft X-ray (1–10 nm) and far ultraviolet (UV) solar radiation ionization of molecular
312:
On July 26, 1963, the first operational geosynchronous satellite Syncom 2 was launched. On board radio beacons on this satellite (and its successors) enabled – for the first time – the measurement of
3051:
Günzkofer, F.; Pokhotelov, D.; Stober, G.; et al. (2022-09-25). "Determining the Origin of Tidal
Oscillations in the Ionospheric Transition Region With EISCAT Radar and Global Simulation Data".
1323:
1435:
is the frequency below which a radio wave fails to penetrate a layer of the ionosphere at the incidence angle required for transmission between two specified points by refraction from the layer.
781:
is a mathematical description of the ionosphere as a function of location, altitude, day of year, phase of the sunspot cycle and geomagnetic activity. Geophysically, the state of the ionospheric
413:
at these frequencies contain sufficient energy to dislodge an electron from a neutral gas atom or molecule upon absorption. In this process the light electron obtains a high velocity so that the
1724:
960:
3106:
316:(TEC) variation along a radio beam from geostationary orbit to an earth receiver. (The rotation of the plane of polarization directly measures TEC along the path.) Australian geophysicist
1668:, which gave the technique its name. Their power spectrum contains information not only on the density, but also on the ion and electron temperatures, ion masses and drift velocities.
2034:
1871:
includes an ionosphere that ranges from about 880 to 1,300 km (550 to 810 mi) in altitude and contains carbon compounds. Ionospheres have also been observed at
2341:
1414:
3009:
1177:
Additional ionization can also occur from direct heating/ionization as a result of huge motions of charge in lightning strikes. These events are called early/fast.
1148:
During a geomagnetic storm the F₂ layer will become unstable, fragment, and may even disappear completely. In the
Northern and Southern polar regions of the Earth
1218:. This communication method is variable and unreliable, with reception over a given path depending on time of day or night, the seasons, weather, and the 11-year
990:
oscillations in the lower ionosphere move plasma up and across the magnetic field lines. This sets up a sheet of electric current in the E region which, with the
195:
of the ionosphere which bears his name. Heaviside's proposal included means by which radio signals are transmitted around the Earth's curvature. Also in 1902,
1166:
Lightning can cause ionospheric perturbations in the D-region in one of two ways. The first is through VLF (very low frequency) radio waves launched into the
340:
that surrounds the Earth, stretching from a height of about 50 km (30 mi) to more than 1,000 km (600 mi). It exists primarily due to
140:
postulated that an electrically conducting region of the atmosphere could account for observed variations of Earth's magnetic field. Sixty years later,
1335:
The
Maximum Usable Frequency (MUF) is defined as the upper frequency limit that can be used for transmission between two points at a specified time.
1189:
layer was indeed enhanced as a result of lightning activity. Their subsequent research has focused on the mechanism by which this process can occur.
3129:
3102:
2209:
1709:
1279:
of the ionosphere, then the electrons cannot respond fast enough, and they are not able to re-radiate the signal. It is calculated as shown below:
3463:
2502:
2388:
1341:
994:
magnetic field, forces ionization up into the F layer, concentrating at ± 20 degrees from the magnetic equator. This phenomenon is known as the
2004:
1604:
642:
or simply the
Heaviside layer. Its existence was predicted in 1902 independently and almost simultaneously by the American electrical engineer
180:
has contested this, however, based on theoretical and experimental work. However, Marconi did achieve transatlantic wireless communications in
1119:
ionization of the D and E layers. PCA's typically last anywhere from about an hour to several days, with an average of around 24 to 36 hours.
1735:
In empirical models of the ionosphere such as
Nequick, the following indices are used as indirect indicators of the state of the ionosphere.
460:
is tipped away from the Sun, thus there is less received solar radiation. Radiation received also varies with geographical location (polar,
1789:-index uses a semi-logarithmic scale from 0 to 9 to measure the strength of the horizontal component of the geomagnetic field. The Boulder
2304:
3034:
2980:
808:(IRI), which is based on data and specifies the four parameters just mentioned. The IRI is an international project sponsored by the
2778:
1845:
1006:
The worldwide solar-driven wind results in the so-called Sq (solar quiet) current system in the E region of the Earth's ionosphere (
417:
of the created electronic gas is much higher (of the order of thousand K) than the one of ions and neutrals. The reverse process to
2362:
2196:
Scientific
Memoirs, Selected from the Transactions of Foreign Academies of Science and Learned Societies, and from Foreign Journals
1929:
278:
first measured the height and density of the ionosphere. This permitted the first complete theory of short-wave radio propagation.
540:
The D layer is the innermost layer, 48 to 90 km (30 to 56 mi) above the surface of the Earth. Ionization here is due to
371:, the atmosphere is so thin that free electrons can exist for short periods of time before they are captured by a nearby positive
1716:
1614:
Scientists are also examining the ionosphere by the changes to radio waves, from satellites and stars, passing through it. The
754:
ions decreases and lighter ions such as hydrogen and helium become dominant. This region above the F layer peak and below the
3297:
3225:
3206:
3159:
2745:
2077:
1285:
3395:
3683:
3426:
813:
1484:
There are a number of models used to understand the effects of the ionosphere on global navigation satellite systems. The
1251:
A qualitative understanding of how an electromagnetic wave propagates through the ionosphere can be obtained by recalling
428:
Ionization depends primarily on the Sun and its Extreme Ultraviolet (EUV) and X-ray irradiance which varies strongly with
3456:
3002:
2302:
Fessenden and Marconi: Their Differing Technologies and Transatlantic Experiments During the First Decade of this Century
2168:
Gauss, Carl Friedrich (1839). "Allgemeine Theorie des Erdmagnetismus ". In Gauss, Carl Friedrich; Weber, Wilhelm (eds.).
1837:
1748:. R12 is a 12 months average of daily sunspot numbers. The two indices have been shown to be correlated with each other.
448:
events that can increase ionization in the polar regions. Thus the degree of ionization in the ionosphere follows both a
2644:
2524:
1919:
1853:
1113:
805:
3370:
3187:
2654:
2152:
2029:
1832:
Objects in the Solar System that have appreciable atmospheres (i.e., all of the major planets and many of the larger
1535:
uses plasma contactors and the ionosphere as parts of a circuit to extract energy from the Earth's magnetic field by
1075:
897:
513:
layer persists by day and night and is the main region responsible for the refraction and reflection of radio waves.
440:
and accompanying increases in EUV and X-ray irradiance, particularly during episodic magnetic eruptions that include
218:
2384:
worldradiohistory.com: Broadcast listening in the pioneer days of radio on the short waves, 1923 1945 Jerome S. Berg
1057:
879:
635:
the height of the E layer maximum increases the range to which radio waves can travel by reflection from the layer.
2144:
1593:
3154:. IEE Electromagnetic Waves Series #31. London, UK: Peter Peregrinus Ltd/The Institution of Electrical Engineers.
933:
produces rough echo traces, seen predominantly at night and at higher latitudes, and during disturbed conditions.
168:
and a power of 100 times more than any radio signal previously produced. The message received was three dits, the
1794:
706:
Main gases of the ionosphere (about 50 km; 31 miand above on this chart) vary considerably by altitude
3449:
1958:
1501:
1094:
1053:
875:
471:
3405:
2114:
1800:
The geomagnetic activity levels of the Earth are measured by the fluctuation of the Earth's magnetic field in
468:, and equatorial regions). There are also mechanisms that disturb the ionosphere and decrease the ionization.
3416:
1248:
ionosphere is less than the radio frequency, and if the electron density in the ionosphere is great enough.
836:(TEC). Since 1999 this model is "International Standard" for the terrestrial ionosphere (standard TS16457).
3678:
2554:
2221:"Carl Friedrich Gauss – General Theory of Terrestrial Magnetism – a revised translation of the German text"
1999:
1525:
829:
639:
614:
608:
192:
3421:
2400:
1271:
is the limiting frequency at or below which a radio wave is reflected by an ionospheric layer at vertical
1586:
1272:
1049:
921:
allow deducing, via computation, the true shape of the different layers. Nonhomogeneous structure of the
871:
809:
655:
145:
17:
3388:
3126:
436:
active regions there are on the Sun at any one time. Sunspot active regions are the source of increased
309:
satellites in 1969 and 1971, further AEROS-A and -B in 1972 and 1975, all for measuring the ionosphere.
3571:
2069:
2057:
1578:
572:. Recombination rates are high in the D layer, so there are many more neutral air molecules than ions.
261:
152:) using a 152.4 m (500 ft) kite-supported antenna for reception. The transmitting station in
2498:
2383:
1978:
1973:
1924:
1681:
1536:
1007:
983:
422:
320:
from 1969 onwards was using this technique to monitor the atmosphere above Australia and Antarctica.
1652:, Elsevier Amsterdam, 1961 (translations into Chinese, French, Japanese and Russian are available).
2803:
1944:
1215:
1038:
860:
684:
445:
1459:
1042:
864:
222:
211:
109:
1141:
Geomagnetic storms and ionospheric storms are temporary and intense disturbances of the Earth's
2427:
The letter, dated 8 November 1926, was addressed to the Secretary of the Radio Research Board.
1968:
1560:
Scientists explore the structure of the ionosphere by a wide variety of methods. They include:
1512:
broadcasts 3 coefficients to compute the effective ionization level, which is then used by the
1479:
1171:
833:
680:
581:
313:
181:
89:
2191:
290:
has developed a theory of electromagnetic wave propagation in plasmas such as the ionosphere.
3585:
3408:
Layman Level Explanations Of "Seemingly" Mysterious 160 Meter (MF/HF) Propagation Occurrences
2841:
Wu, Tsung-Yu; Liu, Jann-Yenq; Chang, Loren C.; Lin, Chien-Hung; Chiu, Yi-Chung (2021-07-19).
2576:
2301:
2169:
1528:
1399:
1120:
1011:
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352:
317:
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157:
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special receivers to detect how the reflected waves have changed from the transmitted waves.
3348:
3251:
2700:
2609:
2445:
2232:
1760:
from the Sun, a parameter more closely related to the ionization levels in the ionosphere.
719:(UV, 10–100 nm) radiation ionizing atomic oxygen. The F layer consists of one layer (F
137:
2972:
1547:
1123:
can also release energetic protons that enhance D-region absorption in the polar regions.
8:
3673:
3657:
3472:
2019:
1939:
1868:
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1665:
1645:
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702:
85:
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2843:"Equatorial ionization anomaly response to lunar phase and stratospheric sudden warming"
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2009:
1669:
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363:, followed by the mesosphere. In the stratosphere incoming solar radiation creates the
267:
230:
1704:
paths as it watches the GNSS satellite rise or set behind the Earth. Using an Inverse
675:
286:
researched the topic of radio propagation of very long radio waves in the ionosphere.
176:. To reach Newfoundland the signal would have to bounce off the ionosphere twice. Dr.
3366:
3293:
3281:
3221:
3202:
3183:
3155:
2943:
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2823:
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2073:
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The project involves more than 11 countries and multiple radars in both hemispheres.
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1136:
1132:
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797:
766:
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207:
141:
117:
2895:"NASA Scientific Visualization Studio | Interface to Space: The Equatorial Fountain"
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910:
3609:
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3259:
3060:
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2870:
2854:
2815:
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306:
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inadvertently provided evidence of the first radio modification of the ionosphere;
253:
239:
188:
105:
45:
3592:
3324:
2363:"On the elevation of the electrically conducting strata of the earth's atmosphere"
456:. There is also a seasonal dependence in ionization degree since the local winter
3133:
2308:
2098:
1880:
1745:
1223:
946:
the summertime loss overwhelms the increase in summertime production, and total F
437:
429:
402:
287:
283:
3236:
3597:
2919:
2858:
1705:
1696:
1564:
passive observations of optical and radio emissions generated in the ionosphere
1240:
740:
589:
588:. A common example of the D layer in action is the disappearance of distant AM
520:
Ionospheric sub-layers from night to day indicating their approximate altitudes
384:
3441:
1781:-indices are a measurement of the behavior of the horizontal component of the
982:
layer at the equator and crests at about 17 degrees in magnetic latitude. The
959:
359:, extends from the surface to about 10 km (6 mi). Above that is the
3667:
2935:
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2827:
2629:
2287:
1934:
1907:
1884:
1876:
1227:
1219:
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465:
275:
203:
113:
3292:, Collection Grenoble Sciences, Université Joseph Fourier Grenoble I, 2000.
3272:
2804:"Some features of the equatorial anomaly revealed by ionospheric tomography"
2621:
2516:
2409:. No. 24473. The New York Times Company. 25 January 1925. pp. 1, 4
116:. It has practical importance because, among other functions, it influences
3621:
3498:
3488:
2691:
Rose, D.C.; Ziauddin, Syed (June 1962). "The polar cap absorption effect".
2670:
2245:
2220:
2060:(2003) . "ionosphere". In Peter Roach; James Hartmann; Jane Setter (eds.).
1836:) generally produce ionospheres. Planets known to have ionospheres include
1809:
1805:
1532:
1149:
755:
557:
553:
541:
441:
368:
360:
177:
93:
2802:
Andreeva, E. S.; Franke, S. J.; Yeh, K. C.; Kunitsyn, V. E. (2000-08-15).
2178:] (in German). Leipzig, (Germany): Weidmanns' Bookshop. pp. 1–57.
1386:{\displaystyle f_{\text{muf}}={\frac {f_{\text{critical}}}{\sin \alpha }}}
3548:
3531:
3521:
3483:
3263:
3064:
2819:
2024:
1619:
1244:
1100:
788:
585:
453:
414:
390:
364:
356:
341:
274:
in 1947 for his confirmation in 1927 of the existence of the ionosphere.
271:
125:
2263:
1447:
144:
received the first trans-Atlantic radio signal on December 12, 1901, in
3553:
3516:
3493:
3400:
3316:
2712:
2279:
2176:
Findings from the Observations of the Magnetic Society in the Year 1838
1913:
1649:
627:
576:
545:
496:
418:
398:
302:
298:
169:
97:
81:
3361:
3336:
2961:. Advisory Group for Aerospace Research and Development. pp. 1–6.
2458:
2433:
2311:". International Conference on 100 Years of Radio, 5–7 September 1995.
2171:
Resultate aus den Beobachtungen des Magnetischen Vereins im Jahre 1838
1827:
30:
3526:
3503:
3003:"Ionospheric Correction Algorithm for Galileo Single Frequency Users"
2140:
2065:
1872:
1712:
of refractivity at that tangent point on earth can be reconstructed.
1641:
1207:
1161:
828:, Millstone Hill, Malvern, St Santin), the ISIS and Alouette topside
817:
744:
549:
165:
161:
101:
3396:
Amsat-Italia project on Ionospheric propagation (ESA SWENET website)
1027:
849:
524:
2959:
High Frequency Radio Communications with Emphasis on Polar Problems
2014:
1902:
1897:
1631:
922:
918:
711:
697:
337:
329:
2894:
2035:
TIMED (Thermosphere Ionosphere Mesosphere Energetics and Dynamics)
88:, from about 48 km (30 mi) to 965 km (600 mi)
3535:
2190:
Gauss, Carl Friedrich; Sabine, Elizabeth Juliana, trans. (1841).
1983:
1857:
1777:
1771:
1421:
1211:
1203:
973:
732:
461:
433:
301:
was launched to study the ionosphere. Following its success were
199:
discovered some of the ionosphere's radio-electrical properties.
2198:. London, England: Richard and John E. Taylor. pp. 184–251.
1088:
986:
lines are horizontal at the magnetic equator. Solar heating and
3431:
3406:
NZ4O 160 Meter (Medium Frequency)Radio Propagation Theory Notes
2546:
1963:
1849:
1574:
751:
619:
410:
294:
153:
149:
1672:
radars can also measure neutral atmosphere movements, such as
839:
72:
3311:, Springer-Verlag Berlin Heidelberg, pp. 189–220, 2007.
2646:
Atmospheric and Space Sciences: Neutral Atmospheres: Volume 1
1952:
1861:
1255:. Since the ionosphere is a plasma, it can be shown that the
736:
457:
444:
that increase ionization on the sunlit side of the Earth and
394:
375:. The number of these free electrons is sufficient to affect
257:
121:
816:(URSI). The major data sources are the worldwide network of
727:) often forms in the electron density profile. Because the F
723:) at night, but during the day, a secondary peak (labelled F
3290:
Du Soleil à la Terre, Aéronomie et météorologie de l'espace
1841:
1753:
1700:
1488:
is currently used to compensate for ionospheric effects in
1425:
987:
978:
It is the occurrence of a trough in the ionization in the F
762:
731:
layer remains by day and night, it is responsible for most
333:
60:
48:
3616:
3411:
3180:
The Earth's Ionosphere: Plasma Physics and Electrodynamics
2600:
Chapman, Sydney (1950). "Upper atmospheric nomenclature".
2517:"Firsts in the Space Race. From an Australian perspective"
54:
3050:
2801:
2547:"Elizabeth A. Essex-Cohen Ionospheric Physics Papers etc"
2351:
be the sea on one side and the upper layer on the other."
1489:
926:
449:
372:
345:
136:
As early as 1839, the German mathematician and physicist
3436:
2476:
Ratcliffe, J.A. (1975). "Robert Alexander Watson-Watt".
1585:, Advanced Modular Incoherent Scatter Radar (AMISR) and
1516:
model to compute a range delay along the line-of-sight.
1243:
in the wave forces the electrons in the ionosphere into
804:
observations. One of the most widely used models is the
474:
proposed that the region below the ionosphere be called
260:
ran a series of experiments in 2017 using the eponymous
3401:
NZ4O Solar Space Weather & Geomagnetic Data Archive
3083:
Department of Physics and Astronomy. Uppsala University
1801:
1640:
of the ionospheric layers and which are measured by an
1622:, was originally intended to study Earth's ionosphere.
1318:{\displaystyle f_{\text{critical}}=9\times {\sqrt {N}}}
1114:
Solar particle event § Polar cap absorption events
3103:"Mars Express: First global map of martian ionosphere"
1531:, which uses the ionosphere, is being researched. The
1107:
1017:
367:. At heights of above 80 km (50 mi), in the
3569:
3417:
Encyclopædia Britannica, Ionosphere and magnetosphere
3337:"Ionospheres: Physics, Plasma Physics, and Chemistry"
1567:
bouncing radio waves of different frequencies from it
1402:
1344:
1288:
69:
66:
63:
57:
3171:
The Upper Atmosphere and Solar-Terrestrial Relations
2920:"Receiver Designs for Low-Latency HF Communications"
2491:
2478:
Biographical Memoirs of Fellows of the Royal Society
575:
Medium frequency (MF) and lower high frequency (HF)
432:. The more magnetically active the Sun is, the more
2218:
1828:
Ionospheres of other planets and natural satellites
1202:Due to the ability of ionized atmospheric gases to
650:(1850–1925). In 1924 its existence was detected by
51:
3323:
1715:Major GNSS radio occultation missions include the
1438:
1408:
1385:
1317:
1275:. If the transmitted frequency is higher than the
2348:. Vol. 33 (10th ed.). pp. 213–235.
3665:
963:Electric currents created in sunward ionosphere.
792:and, since several species of ions are present,
3471:
2577:"The Ionosphere | Center for Science Education"
3053:Journal of Geophysical Research: Space Physics
2005:High Frequency Active Auroral Research Program
1605:High Frequency Active Auroral Research Program
1239:When a radio wave reaches the ionosphere, the
379:. This portion of the atmosphere is partially
3457:
3309:Handbook of the Solar-Terrestrial Environment
2840:
1676:, after making assumptions about ion-neutral
1089:X-rays: sudden ionospheric disturbances (SID)
34:Relationship of the atmosphere and ionosphere
2924:IEEE Transactions on Wireless Communications
2917:
2690:
2208:: CS1 maint: multiple names: authors list (
1730:
1655:
1594:Super Dual Auroral Radar Network (SuperDARN)
1494:US Air Force Geophysical Research Laboratory
2995:
2733:
2593:
2219:Glassmeier, K.-H; Tsurutani, B. T. (2014).
2189:
1763:
1056:. Unsourced material may be challenged and
878:. Unsourced material may be challenged and
840:Persistent anomalies to the idealized model
3464:
3450:
3334:
3168:
1234:
252:In the early 1930s, test transmissions of
3360:
3271:
3237:"International Reference Ionosphere 2000"
2918:Arikan, Toros; Singer, Andrew C. (2021).
2874:
2740:. Exeter Books (A Bison Book), New York.
2475:
2457:
2339:
2244:
2192:"General theory of terrestrial magnetism"
1687:
1603:A variety of experiments, such as HAARP (
1076:Learn how and when to remove this message
967:Within approximately ± 20 degrees of the
898:Learn how and when to remove this message
3437:European Incoherent Scatter radar system
3196:
2892:
2684:
2671:"Neutrosphere - Glossary of Meteorology"
2431:
2360:
1930:Magnetospheric electric convection field
1756:spacecraft that measures the background
1546:
1420:, the angle of the wave relative to the
1001:
958:
909:
701:
523:
515:
495:
387:which is referred to as the ionosphere.
29:
27:Ionized part of Earth's upper atmosphere
3321:
3234:
2599:
2261:
1636:Ionograms show the virtual heights and
491:
131:
14:
3666:
3199:Radio Amateurs Guide to the Ionosphere
3177:
3149:
2557:from the original on 11 September 2017
2527:from the original on 11 September 2017
2401:"Sun Affects Radio, Observations Show"
2323:IEEE Antennas and Propagation Magazine
1551:Properties of Earth's Upper Atmosphere
1328:where N = electron density per m and f
1197:
800:depends uniquely on electron density.
646:(1861–1939) and the British physicist
237:in a letter published only in 1969 in
3445:
3215:
3015:from the original on 10 February 2018
2888:
2886:
2797:
2795:
2727:
2642:
2167:
2134:
2056:
1519:
1152:will be observable in the night sky.
954:
785:may be described by four parameters:
560:can generate hard X-rays (wavelength
2973:"ION Fellow - Mr. John A. Klobuchar"
2956:
2899:NASA Scientific Visualization Studio
2775:"International Reference Ionosphere"
2432:Gardiner, G. W. (13 December 1969).
2321:"Marconi and the History of Radio".
2264:"Wireless telegraphic communication"
2128:
2112:
1592:coherent scatter radars such as the
1442:
1054:adding citations to reliable sources
1021:
876:adding citations to reliable sources
843:
814:International Union of Radio Science
772:
452:(time of day) cycle and the 11-year
3335:Schunk, R. W.; Nagy, A. F. (2009).
3220:. Dordrecht: Kluwer Academic Publ.
2983:from the original on 4 October 2017
2262:Marconi, Guglielmo (January 2002).
1108:Protons: polar cap absorption (PCA)
1018:Ephemeral ionospheric perturbations
787:electron density, electron and ion
24:
3218:Wave Propagation in the Ionosphere
3127:NASA/JPL: Titan's upper atmosphere
3035:"Ionospheric Corrections for GNSS"
2883:
2792:
2673:. Glossary.ametsoc.org. 2012-01-26
2225:History of Geo- and Space Sciences
2137:Wave Propagation in the Ionosphere
1920:International Reference Ionosphere
1738:
1492:. This model was developed at the
806:International Reference Ionosphere
769:satellites to study the F region.
758:is called the topside ionosphere.
25:
3695:
3380:
2737:The Encyclopedia of US Spacecraft
2367:The Electrical World and Engineer
2030:Sura Ionospheric Heating Facility
936:
750:Above the F layer, the number of
638:This region is also known as the
3651:
3639:
3627:
3615:
3603:
3591:
3579:
3432:Super Dual Auroral Radar Network
3422:Current Space Weather Conditions
3182:(2nd ed.). Academic Press.
2505:from the original on 2017-02-20.
2361:Kennelly, A.E. (15 March 1902).
1446:
1026:
914:Overview of ionosphere phenomena
848:
128:that travel through this layer.
112:and forms the inner edge of the
108:. It plays an important role in
44:
3120:
3109:from the original on 2015-09-10
3095:
3071:
3044:
3027:
2965:
2950:
2911:
2834:
2781:from the original on 2011-02-23
2767:
2758:
2663:
2636:
2602:Journal of Geophysical Research
2569:
2539:
2509:
2434:"Origin of the term Ionosphere"
2421:
2393:
2377:
2354:
1795:Boulder Geomagnetic Observatory
1542:
1439:GPS/GNSS ionospheric correction
1192:
1099:When the Sun is active, strong
544:-alpha hydrogen radiation at a
104:. The ionosphere is ionized by
3386:Gehred, Paul, and Norm Cohen,
2333:
2314:
2294:
2255:
2161:
2106:
2099:Merriam-Webster.com Dictionary
2086:
2062:English Pronouncing Dictionary
2050:
1095:Sudden ionospheric disturbance
191:proposed the existence of the
13:
1:
3173:. Cambridge University Press.
3143:
2643:Yiğit, Erdal (27 July 2015).
328:The ionosphere is a shell of
323:
217:In 1925, observations during
92:, a region that includes the
3288:J. Lilensten, P.-L. Blelly:
2893:Bridgman, Tom (2018-01-31).
2808:Geophysical Research Letters
2194:. In Taylor, Richard (ed.).
2115:"Earth's Atmospheric Layers"
2113:Zell, Holly (2 March 2015).
2000:Canadian Geospace Monitoring
1625:
1155:
582:absorption of HF radio waves
580:This is the main reason for
229:In 1926, Scottish physicist
7:
3684:Radio frequency propagation
3326:Atmospheric Electrodynamics
3307:, in: Y. Kamide, A. Chian,
2025:Upper-atmospheric lightning
1890:
1555:
1504:navigation system uses the
810:Committee on Space Research
715:production is dominated by
661:
160:to produce a signal with a
10:
3700:
3347:(46) (2nd ed.): 556.
3330:. Berlin: Springer Verlag.
3303:P.-L. Blelly, D. Alcaydé:
3169:Hargreaves, J. K. (1992).
2859:10.1038/s41598-021-94326-x
2430:The letter was quoted in:
2340:Heaviside, Oliver (1902).
2070:Cambridge University Press
1959:Earth–ionosphere waveguide
1793:-index is measured at the
1629:
1477:
1231:where milliseconds count.
1159:
1130:
1111:
1092:
695:
691:
606:
602:
535:
164:of approximately 500
3544:
3512:
3479:
3412:USGS Geomagnetism Program
3197:McNamara, Leo F. (1994).
1979:Line-of-sight propagation
1974:Ionospheric scintillation
1925:Ionospheric dynamo region
1731:Indices of the ionosphere
1682:ionospheric dynamo region
1656:Incoherent scatter radars
1537:electromagnetic induction
1126:
1008:ionospheric dynamo region
592:stations in the daytime.
332:and electrically charged
3427:Current Solar X-Ray Flux
3389:SWPC's Radio User's Page
3235:Bilitza, Dieter (2001).
3150:Davies, Kenneth (1990).
3008:. Galileo Open Service.
2936:10.1109/TWC.2020.3046475
2346:Encyclopaedia Britannica
2043:
1945:Van Allen radiation belt
1764:Geomagnetic disturbances
747:) radio communications.
739:waves and long distance
640:Kennelly–Heaviside layer
609:Kennelly–Heaviside layer
446:solar energetic particle
193:Kennelly–Heaviside layer
146:St. John's, Newfoundland
3079:"Planetary ionospheres"
2622:10.1029/JZ055i004p00395
1409:{\displaystyle \alpha }
1235:Mechanism of refraction
1206:high frequency (HF, or
941:At mid-latitudes, the F
683:makes VHF-operating by
351:The lowest part of the
223:Dr. Alfred N. Goldsmith
212:amateur radio operators
110:atmospheric electricity
3178:Kelley, M. C. (2009).
2777:. Ccmc.gsfc.nasa.gov.
2499:"Gakona HAARPoon 2017"
2246:10.5194/hgss-5-11-2014
1969:Ionospheric absorption
1688:GNSS radio occultation
1552:
1480:Total electron content
1410:
1387:
1319:
1172:electron precipitation
1121:Coronal mass ejections
984:Earth's magnetic field
964:
915:
834:total electron content
707:
681:Sporadic E propagation
532:
521:
501:
314:total electron content
250:
182:Glace Bay, Nova Scotia
35:
2693:Space Science Reviews
2217:English translation:
2188:English translation:
1577:, Sondre Stromfjord,
1550:
1529:electrodynamic tether
1498:John (Jack) Klobuchar
1411:
1388:
1320:
1160:Further information:
1112:Further information:
1012:equatorial electrojet
1002:Equatorial electrojet
962:
913:
705:
644:Arthur Edwin Kennelly
527:
519:
499:
318:Elizabeth Essex-Cohen
245:
197:Arthur Edwin Kennelly
158:spark-gap transmitter
120:to distant places on
33:
3322:Volland, H. (1984).
3264:10.1029/2000RS002432
3065:10.1029/2022JA030861
2820:10.1029/1999GL003725
2734:Yenne, Bill (1985).
1638:critical frequencies
1400:
1342:
1286:
1050:improve this section
872:improve this section
492:Layers of ionization
305:in 1965 and the two
233:introduced the term
138:Carl Friedrich Gauss
132:History of discovery
3679:Terrestrial plasmas
3353:2001EOSTr..82..556K
3256:2001RaSc...36..261B
3136:Accessed 2010-08-25
2957:Lied, Finn (1967).
2705:1962SSRv....1..115R
2614:1950JGR....55..395C
2450:1969Natur.224.1096G
2237:2014HGSS....5...11G
2020:Soft gamma repeater
1940:Schumann resonances
1869:atmosphere of Titan
1819:-index, called the
1678:collision frequency
1646:William Roy Piggott
1573:radars such as the
1262:Dispersion (optics)
1226:frequencies, as do
1198:Radio communication
996:equatorial fountain
824:radars (Jicamarca,
717:extreme ultraviolet
597:solar proton events
556:(NO). In addition,
500:Ionospheric layers.
344:radiation from the
156:, Cornwall, used a
86:atmosphere of Earth
3473:Earth's atmosphere
3317:10.1007/11367758_8
3216:Rawer, K. (1993).
3132:2011-05-11 at the
2847:Scientific Reports
2713:10.1007/BF00174638
2406:The New York Times
2307:2009-01-23 at the
2300:John S. Belrose, "
2280:10.1007/bf02836176
2135:Rawer, K. (1993).
2102:. Merriam-Webster.
2010:Ionospheric heater
1834:natural satellites
1699:technique where a
1670:Incoherent scatter
1661:Incoherent scatter
1571:incoherent scatter
1553:
1520:Other applications
1458:. You can help by
1406:
1383:
1315:
1269:critical frequency
965:
955:Equatorial anomaly
916:
822:incoherent scatter
761:From 1972 to 1975
708:
652:Edward V. Appleton
533:
522:
502:
483:neutral atmosphere
353:Earth's atmosphere
268:Edward V. Appleton
231:Robert Watson-Watt
184:, one year later.
124:. It also affects
84:part of the upper
36:
3567:
3566:
3362:10.1029/01EO00328
3298:978-2-86883-467-6
3227:978-0-7923-0775-4
3208:978-0-89464-804-5
3161:978-0-86341-186-1
3152:Ionospheric Radio
2814:(16): 2465–2468.
2747:978-0-671-07580-4
2459:10.1038/2241096a0
2079:978-3-12-539683-8
1821:planetary A-index
1783:geomagnetic field
1693:Radio occultation
1674:atmospheric tides
1616:Arecibo Telescope
1476:
1475:
1424:, and sin is the
1381:
1367:
1352:
1313:
1296:
1137:Ionospheric storm
1133:Geomagnetic storm
1086:
1085:
1078:
908:
907:
900:
812:(COSPAR) and the
798:Radio propagation
794:ionic composition
779:ionospheric model
773:Ionospheric model
767:AEROS and AEROS B
529:Lightning sprites
377:radio propagation
280:Maurice V. Wilkes
262:Luxembourg Effect
208:Radio Act of 1912
142:Guglielmo Marconi
118:radio propagation
96:and parts of the
16:(Redirected from
3691:
3656:
3655:
3654:
3644:
3643:
3642:
3632:
3631:
3630:
3620:
3619:
3608:
3607:
3606:
3596:
3595:
3584:
3583:
3582:
3575:
3466:
3459:
3452:
3443:
3442:
3376:
3364:
3341:Eos Transactions
3331:
3329:
3285:
3275:
3273:2060/19910021307
3241:
3231:
3212:
3193:
3174:
3165:
3137:
3124:
3118:
3117:
3115:
3114:
3099:
3093:
3092:
3090:
3089:
3075:
3069:
3068:
3048:
3042:
3041:
3039:
3031:
3025:
3024:
3022:
3020:
3014:
3007:
2999:
2993:
2992:
2990:
2988:
2969:
2963:
2962:
2954:
2948:
2947:
2930:(5): 3005–3015.
2915:
2909:
2908:
2906:
2905:
2890:
2881:
2880:
2878:
2838:
2832:
2831:
2799:
2790:
2789:
2787:
2786:
2771:
2765:
2762:
2756:
2751:
2731:
2725:
2724:
2688:
2682:
2681:
2679:
2678:
2667:
2661:
2660:
2640:
2634:
2633:
2597:
2591:
2590:
2588:
2587:
2573:
2567:
2566:
2564:
2562:
2543:
2537:
2536:
2534:
2532:
2513:
2507:
2506:
2495:
2489:
2485:
2471:
2461:
2425:
2419:
2418:
2416:
2414:
2397:
2391:
2381:
2375:
2374:
2358:
2352:
2349:
2337:
2331:
2330:
2318:
2312:
2298:
2292:
2291:
2259:
2253:
2250:
2248:
2213:
2207:
2199:
2179:
2165:
2159:
2158:
2132:
2126:
2125:
2123:
2122:
2110:
2104:
2103:
2090:
2084:
2083:
2054:
1706:Abel's transform
1471:
1468:
1450:
1443:
1433:cutoff frequency
1418:angle of arrival
1415:
1413:
1412:
1407:
1392:
1390:
1389:
1384:
1382:
1380:
1369:
1368:
1365:
1359:
1354:
1353:
1350:
1324:
1322:
1321:
1316:
1314:
1309:
1298:
1297:
1294:
1277:plasma frequency
1257:refractive index
1253:geometric optics
1174:" (LEP) events.
1145:and ionosphere.
1081:
1074:
1070:
1067:
1061:
1030:
1022:
969:magnetic equator
903:
896:
892:
889:
883:
852:
844:
648:Oliver Heaviside
563:
254:Radio Luxembourg
189:Oliver Heaviside
79:
78:
75:
74:
71:
68:
65:
62:
59:
56:
53:
50:
21:
3699:
3698:
3694:
3693:
3692:
3690:
3689:
3688:
3664:
3663:
3662:
3652:
3650:
3640:
3638:
3628:
3626:
3614:
3604:
3602:
3590:
3580:
3578:
3570:
3568:
3563:
3540:
3508:
3475:
3470:
3383:
3373:
3239:
3228:
3209:
3190:
3162:
3146:
3141:
3140:
3134:Wayback Machine
3125:
3121:
3112:
3110:
3101:
3100:
3096:
3087:
3085:
3077:
3076:
3072:
3049:
3045:
3037:
3033:
3032:
3028:
3018:
3016:
3012:
3005:
3001:
3000:
2996:
2986:
2984:
2971:
2970:
2966:
2955:
2951:
2916:
2912:
2903:
2901:
2891:
2884:
2839:
2835:
2800:
2793:
2784:
2782:
2773:
2772:
2768:
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2759:
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2551:harveycohen.net
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2145:Kluwer Academic
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2055:
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1990:
1893:
1830:
1818:
1766:
1746:radio telescope
1741:
1739:Solar intensity
1733:
1690:
1658:
1634:
1628:
1558:
1545:
1522:
1486:Klobuchar model
1482:
1472:
1466:
1463:
1456:needs expansion
1441:
1401:
1398:
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1224:shortwave radio
1200:
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1131:Main articles:
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735:propagation of
730:
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571:
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564:) that ionize N
561:
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512:
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494:
438:coronal heating
403:solar radiation
383:and contains a
326:
288:Vitaly Ginzburg
284:J. A. Ratcliffe
221:in New York by
219:a solar eclipse
172:for the letter
134:
106:solar radiation
90:above sea level
47:
43:
28:
23:
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15:
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1697:remote sensing
1689:
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1579:Millstone Hill
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696:Main article:
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607:Main article:
604:
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590:broadcast band
569:
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552:(nm) ionizing
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472:Sydney Chapman
430:solar activity
325:
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270:was awarded a
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2058:Jones, Daniel
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1935:Protonosphere
1933:
1931:
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1918:
1917:
1916:
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1911:
1909:
1908:Space physics
1906:
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1878:
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1859:
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1847:
1843:
1839:
1835:
1822:
1815:
1811:
1807:
1804:units called
1803:
1799:
1796:
1792:
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1779:
1774:
1773:
1768:
1767:
1761:
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1511:
1507:
1506:NeQuick model
1503:
1499:
1495:
1491:
1487:
1481:
1470:
1461:
1457:
1454:This section
1452:
1449:
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1434:
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1403:
1377:
1374:
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1249:
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1229:
1228:radio amateur
1225:
1221:
1220:sunspot cycle
1217:
1213:
1209:
1205:
1190:
1178:
1175:
1173:
1169:
1168:magnetosphere
1163:
1153:
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1143:magnetosphere
1138:
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1115:
1105:
1102:
1096:
1080:
1077:
1069:
1059:
1055:
1051:
1045:
1044:
1040:
1035:This section
1033:
1029:
1024:
1023:
1015:
1013:
1009:
999:
997:
993:
989:
985:
977:
975:
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961:
952:
934:
932:
928:
924:
920:
912:
902:
899:
891:
881:
877:
873:
867:
866:
862:
857:This section
855:
851:
846:
845:
837:
835:
831:
827:
823:
819:
815:
811:
807:
801:
799:
795:
791:
790:
784:
780:
770:
768:
765:launched the
764:
759:
757:
753:
748:
746:
742:
738:
734:
718:
713:
704:
699:
689:
686:
682:
677:
659:
657:
656:Miles Barnett
653:
649:
645:
641:
636:
630:events, the E
629:
621:
616:
610:
600:
598:
593:
591:
587:
583:
578:
573:
559:
555:
551:
547:
543:
530:
526:
518:
514:
498:
489:
487:
485:
484:
479:
478:
473:
469:
467:
466:mid-latitudes
463:
459:
455:
451:
447:
443:
439:
435:
431:
426:
424:
423:recombination
420:
416:
412:
408:
404:
400:
396:
392:
388:
386:
382:
378:
374:
370:
366:
362:
358:
354:
349:
347:
343:
339:
335:
331:
321:
319:
315:
310:
308:
304:
300:
296:
293:In 1962, the
291:
289:
285:
281:
277:
276:Lloyd Berkner
273:
269:
265:
263:
259:
255:
249:
244:
242:
241:
236:
232:
227:
224:
220:
215:
213:
209:
205:
204:U.S. Congress
202:In 1912, the
200:
198:
194:
190:
185:
183:
179:
175:
171:
167:
163:
159:
155:
151:
147:
143:
139:
129:
127:
123:
119:
115:
114:magnetosphere
111:
107:
103:
99:
95:
91:
87:
83:
77:
41:
32:
19:
3658:Solar System
3558:
3499:Thermosphere
3489:Stratosphere
3387:
3344:
3340:
3325:
3308:
3304:
3289:
3247:
3243:
3217:
3198:
3179:
3170:
3151:
3122:
3111:. Retrieved
3097:
3086:. Retrieved
3082:
3073:
3056:
3052:
3046:
3029:
3017:. Retrieved
2997:
2985:. Retrieved
2976:
2967:
2958:
2952:
2927:
2923:
2913:
2902:. Retrieved
2898:
2853:(1): 14695.
2850:
2846:
2836:
2811:
2807:
2783:. Retrieved
2769:
2760:
2753:
2738:
2735:
2729:
2696:
2692:
2686:
2675:. Retrieved
2665:
2649:. Springer.
2645:
2638:
2605:
2601:
2595:
2584:. Retrieved
2580:
2571:
2559:. Retrieved
2550:
2541:
2529:. Retrieved
2520:
2511:
2493:
2481:
2477:
2441:
2437:
2423:
2411:. Retrieved
2404:
2395:
2379:
2370:
2366:
2356:
2345:
2342:"Telegraphy"
2335:
2326:
2322:
2316:
2296:
2271:
2267:
2257:
2231:(1): 11–62.
2228:
2224:
2195:
2182:
2175:
2170:
2163:
2136:
2130:
2119:. Retrieved
2108:
2097:
2094:"ionosphere"
2088:
2061:
2052:
1994:
1951:
1912:
1866:
1831:
1820:
1813:
1790:
1786:
1782:
1776:
1770:
1757:
1750:
1742:
1734:
1714:
1691:
1659:
1637:
1635:
1613:
1609:
1602:
1559:
1543:Measurements
1533:space tether
1523:
1513:
1509:
1505:
1497:
1493:
1485:
1483:
1467:October 2013
1464:
1460:adding to it
1455:
1430:
1395:
1334:
1327:
1266:
1250:
1238:
1201:
1193:Applications
1179:
1176:
1165:
1147:
1140:
1117:
1101:solar flares
1098:
1072:
1063:
1048:Please help
1036:
1005:
995:
972:
968:
966:
940:
917:
894:
885:
870:Please help
858:
802:
793:
786:
778:
776:
760:
756:plasmasphere
749:
709:
669:
637:
612:
594:
574:
558:solar flares
554:nitric oxide
542:Lyman series
539:
509:layer. The F
503:
488:
482:
481:
477:neutrosphere
476:
475:
470:
442:solar flares
427:
406:
397:and shorter
389:
380:
369:thermosphere
361:stratosphere
350:
327:
311:
292:
266:
251:
248:this series.
246:
238:
234:
228:
216:
206:imposed the
201:
186:
178:Jack Belrose
173:
135:
94:thermosphere
39:
37:
3646:Outer space
3634:Spaceflight
3549:Ozone layer
3532:Thermopause
3522:Stratopause
3484:Troposphere
2977:www.ion.org
2486:See p. 554.
2474:See also:
2214:See p. 229.
1680:across the
1620:Puerto Rico
1618:located in
1526:open system
1245:oscillation
789:temperature
586:cosmic rays
577:radio waves
454:solar cycle
415:temperature
399:wavelengths
391:Ultraviolet
365:ozone layer
357:troposphere
342:ultraviolet
272:Nobel Prize
126:GPS signals
18:Ionospheric
3674:Ionosphere
3668:Categories
3559:Ionosphere
3554:Turbopause
3517:Tropopause
3494:Mesosphere
3305:Ionosphere
3144:References
3113:2015-10-31
3088:2023-06-04
3019:9 February
2904:2024-09-30
2785:2011-11-08
2699:(1): 115.
2677:2022-08-12
2586:2023-04-05
2484:: 549–568.
2413:25 January
2373:(11): 473.
2121:2020-10-23
1914:Geophysics
1758:X-ray flux
1650:Karl Rawer
1478:See also:
1428:function.
1332:is in Hz.
992:horizontal
974:equatorial
818:ionosondes
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546:wavelength
458:hemisphere
419:ionization
324:Geophysics
303:Alouette 2
299:Alouette 1
297:satellite
235:ionosphere
170:Morse code
98:mesosphere
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3610:Astronomy
3527:Mesopause
3504:Exosphere
3282:116976314
2944:233990323
2867:2045-2322
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2630:0148-0227
2288:0971-8044
2268:Resonance
2204:cite book
2141:Dordrecht
2066:Cambridge
1666:coherence
1642:ionosonde
1626:Ionograms
1587:Jicamarca
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1066:July 2024
1037:does not
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888:July 2024
859:does not
745:shortwave
562:< 1 nm
550:nanometre
548:of 121.6
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338:molecules
330:electrons
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162:frequency
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2981:Archived
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1903:Geospace
1898:Aeronomy
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674:layer (
615:E layer
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536:D layer
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