Ionosphere 15097 225829568 2008-07-15T16:21:20Z Reddi 13833 /* History */ [[Image:Atmosphere with Ionosphere.svg|thumb|400px|Relationship of the atmosphere and ionosphere]] The '''ionosphere''' is the uppermost part of the [[Earth's atmosphere|atmosphere]], distinguished because it is [[ionized]] by solar radiation. It plays an important part in [[atmospheric electricity]] and forms the inner edge of the [[magnetosphere]]. It has practical importance because, among other functions, it influences [[radio propagation]] to distant places on the Earth. It is located in the [[Thermosphere]]. ==Geophysics== The lowest part of the [[Earth's atmosphere]] is called the [[troposphere]] and it extends from the surface up to about 10 [[Kilometre|km]] (6 miles). The atmosphere above 10 km is called the [[stratosphere]], followed by the [[mesosphere]]. It is in the stratosphere that incoming solar radiation creates the [[ozone layer]]. At heights of above 80 km (50 miles), in the [[thermosphere]], the atmosphere is so thin that free [[electrons]] can exist for short periods of time before they are captured by a nearby positive [[ion]]. The number of these free electrons is sufficient to affect [[radio propagation]]. This portion of the atmosphere is ''ionized'' and contains a [[Plasma physics|plasma]] which is referred to as the ionosphere. In a plasma, the negative free electrons and the positive ions are attracted to each other by the electromagnetic force, but they are too energetic to stay fixed together in an electrically neutral molecule. [[Solar radiation]] at [[ultraviolet]] (UV) and shorter [[X-Ray]] [[wavelength]]s is considered to be ''ionizing'' since [[photon]]s at these frequencies are capable of dislodging an [[electron]] from a neutral gas [[atom]] or [[molecule]] during a collision. At the same time, however, an opposing process called [[recombination]] begins to take place in which a free electron is "captured" by a positive ion if it moves close enough to it. As the gas density increases at lower altitudes, the recombination process accelerates since the gas molecules and ions are closer together. The point of balance between these two processes determines the degree of ionization present at any given time. The ionization depends primarily on the [[Sun]] and its [[solar variation|activity]]. The amount of ionization in the ionosphere varies greatly with the amount of radiation received from the sun. Thus there is a [[diurnal]] (time of day) effect and a seasonal effect. The local winter [[Earth|hemisphere]] is tipped away from the Sun, thus there is less received solar radiation. The activity of the sun is associated with the [[sunspot cycle]], with more radiation occurring with more sunspots. Radiation received also varies with geographical location (polar, auroral zones, mid-latitudes, and equatorial regions). There are also mechanisms that disturb the ionosphere and decrease the ionization. There are disturbances such as [[solar flare]]s and the associated release of charged particles into the [[solar wind]] which reaches the Earth and interacts with its [[geomagnetic]] field. ==The ionospheric layers== Solar radiation, acting on the different compositions of the atmosphere with height, generates layers of ionization: ===D layer=== The [[D region|D layer]] is the innermost layer, 50 km to 90 km above the surface of the Earth. Ionization here is due to [[Lyman series]]-alpha hydrogen radiation at a [[wavelength]] of 121.5 [[nanometre]] (nm) ionizing [[nitric oxide]] (NO). In addition, when the sun is active with 50 or more sunspots, hard [[X-ray]]s (wavelength < 1 nm) ionize the air (N<sub>2</sub>, O<sub>2</sub>). During the night [[cosmic rays]] produce a residual amount of ionization. Recombination is high in the D layer, thus the net ionization effect is very low and as a result high-frequency (HF) [[radio wave]]s aren't reflected by the D layer. The frequency of collision between electrons and other particles in this region during the day is about 10 million collisions per second. The D layer is mainly responsible for [[Ionospheric absorption|absorption of HF radio waves]], particularly at 10 MHz and below, with progressively smaller absorption as the frequency gets higher. The absorption is small at night and greatest about midday. The layer reduces greatly after sunset, but remains due to [[galactic cosmic ray]]s. A common example of the D layer in action is the disappearance of distant AM [[broadcast band]] stations in the daytime. During [[solar proton event]]s, ionization can reach unusually high levels in the D-region over the high and polar latitudes. Such 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. ===E layer=== The [[Kennelly-Heaviside Layer|E layer]] is the middle layer, 90 km to 120 km 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 [[oxygen]] (O<sub>2</sub>). This layer can only reflect radio waves having frequencies less than about 10 MHz. It has a negative effect on frequencies above 10 MHz due to its partial absorption of these waves. The vertical structure of the E layer is primarily determined by the competing effects of ionization and recombination. At night the E layer begins to disappear because the primary source of ionization is no longer present. This results in an increase in the height where the layer maximizes because recombination is faster in the lower layers. Diurnal changes in the high altitude neutral winds also plays a role. The increase in the height of the E layer maximum increases the range to which radio waves can travel by reflection from the layer. This region is also known as the [[Kennelly-Heaviside Layer]] layer or simply the Heaviside layer. Its existence was predicted in 1902 independently and almost simultaneously by the American electrical engineer [[Arthur Edwin Kennelly]] (1861-1939) and the British physicist [[Oliver Heaviside]] (1850-1925). However, it was not until 1924 that its existence was detected by [[Edward V. Appleton]]. ===E<sub>S</sub>=== The E<sub>s</sub> layer or sporadic E-layer. [[Sporadic E propagation]] is characterized by small clouds of intense ionization, which can support radio wave reflections from 25 – 225 MHz. Sporadic-E events may last for just a few minutes to several hours and make [[Amateur radio high bands|radio amateurs]] very excited, as propagation paths which are generally unreachable, can open up. There are multiple causes of sporadic-E that are still being pursued by researchers. This propagation occurs most frequently during the summer months with major occurrences during the summer, and minor occurrences during the winter. During the summer, this mode is popular due to its high signal levels. The skip distances are generally around 1000km (620 miles). VHF TV and FM broadcast DX'ers also get excited as their signals can be bounced back to earth by Es. Distances for short hop events can be as close as 500 miles or up to 1,400 (or more) for a long, single hop. Douple-hop reception over 2,000 miles is possible, too. ===F layer=== The [[F region|F layer]] or region, also known as the Appleton layer, is 120 km to 400 km above the surface of the Earth. It is the top most layer of the ionosphere. Here extreme ultraviolet (UV, 10–100 nm) solar radiation ionizes atomic [[oxygen]]. The F layer consists of one layer at night, but in the presence of sunlight (during the day), it divides into two layers, labeled F<sub>1</sub> and F<sub>2</sub>. These F layers are responsible for most [[skywave]] propagation of [[radio]] waves, facilitating high frequency (HF, or [[shortwave]]) radio communications over long distances. They are thickest and most effective in refracting radio signals on the side of the earth facing the sun. From 1972 to 1975 [[NASA]] launched the [[AEROS (satellite)|AEROS and AEROS B]] satellites to study the F region.<ref name="Yenne">{{cite book|author=Yenne, Bill|title=''The Encyclopedia of US Spacecraft''|publisher=Exeter Books (A Bison Book), New York|year=1985|id=ISBN 0-671-07580-2}}p.12 '''AEROS'''</ref> ===Ionospheric model=== The atmospheric physics community contributes to the definition and maintenance of an ionospheric model: the International Reference Ionosphere, through a series of academic committees and conferences. As discoveries are made and generally accepted, the model is improved. [[#References|(IRI85-6)]] ==Anomalies to the ideal model== The statements above assumed that each layer was smooth and uniform. In reality the ionosphere is a lumpy, cloudy layer with irregular patches of ionization. ===Winter anomaly=== At mid-latitudes, the F<sub>2</sub> 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 the summertime loss overwhelms the increase in summertime production, and total F<sub>2</sub> 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. ===Equatorial anomaly=== [[Image:Diurnal ionospheric current.jpg|frame|right|Electric currents created in sunward ionosphere.]] Within approximately ± 20 degrees of the ''magnetic equator'', is the ''[[equator]]ial anomaly''. It is the occurrence of a trough of concentrated ionization in the F<sub>2</sub> layer. The Earth's [[magnetic field]] lines are horizontal at the magnetic equator. Solar heating and [[tidal]] 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 [[Horizontal plane|horizontal]] magnetic field, forces ionization up into the F layer, concentrating at ± 20 degrees from the magnetic equator. This phenomenon is known as the ''equatorial fountain''. === Equatorial electrojet === The worldwide solar-driven wind results in the so-called Sq (solar quiet) current system in the E region of the Earth's ionosphere (100-130 km altitude). Resulting from this current is an electrostatic field directed E-W (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 [[equatorial electrojet]]. ==Ionospheric perturbations== ===X-rays: sudden ionospheric disturbances (SID)=== When the sun is active, strong [[solar flare]]s can occur that will hit the Earth with hard X-rays on the sunlit side of the Earth. They will penetrate to the D-region, release electrons which will rapidly increase absorption causing a High Frequency (3-30 MHz) radio blackout. During this time Very Low Frequency (3 - 30 kHz) signals will become 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 ends as the electrons in the D-region recombine rapidly and signal strengths return to normal. ===Protons: polar cap absorption (PCA)=== 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 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. ===Geomagnetic storms=== A [[geomagnetic storm]] is a temporary intense disturbance of the Earth's [[magnetosphere]]. * During a geomagnetic storm the F<sub>2</sub> layer will become unstable, fragment, and may even disappear completely. * In the Northern and Southern pole regions of the Earth [[polar aurora|aurora]] will be observable in the sky. ===Lightning=== [[Lightning]] can cause ionospheric perturbations in the D-region one of two ways. The first is through VLF frequency radio waves launched into the [[magnetosphere]]. 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 Electron Precipitation (LEP) events. 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. ==Radio application== <!-- This section is linked from [[Triple J]] --> [[DX communication]], popular among [[amateur radio]] enthusiasts, is a term given to communication over great distances. Thanks to the property of ionized atmospheric gases to [[refract]] high frequency (HF, or [[shortwave]]) radio energy, the ionosphere can be utilized to "bounce" a transmitted signal back to earth. The signal may then be reflected back into the ionosphere for a second bounce, or [[Hop (telecommunications)|hop]]. ===Mechanism of refraction=== When a radio wave reaches the ionosphere, the [[electric field]] in the wave forces the electrons in the ionosphere into [[oscillation]] 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 ionosphere is less than the radio frequency, and if the electron density in the ionosphere is great enough. The [[critical frequency]] is the limiting frequency at or below which a radio wave is refracted by an ionospheric layer at vertical [[angle of incidence|incidence]]. If the transmitted frequency is higher than the [[plasma frequency]] 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: : <math>f_{critical} = 9 \times 10^{-3} \sqrt{N}</math> where N = electron density per cm<sup>3</sup> and f<sub>critical</sub> is in MHz. 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. : <math>f_{muf} = \frac{f_{critical}}{ \sin \alpha} </math> where <math>\alpha</math> = [[angle of attack]], the angle of the wave relative to the [[horizon]], and sin is the [[sine]] function. The [[cutoff frequency]] 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. ==Other applications== The [[open system]] [[space tether]], which uses the ionosphere, is being researched. The space tether uses plasma contactors and the ionosphere as parts of a circuit to extract energy from the Earth's magnetic field by [[electromagnetic induction]]. ==Measurements== ===Ionograms=== Ionograms show the virtual heights and '''critical frequencies''' of the ionospheric layers and which are measured by an [[ionosonde]]. 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. ===Incoherent scatter radars=== ===Solar flux=== Solar flux is a measurement of the intensity of solar radio emissions at a frequency of 2800 MHz made using a [[radio telescope]] located in [[Ottawa]], Canada. Known also as the 10.7 cm flux (the wavelength of the radio signals at 2800 MHz), this solar radio emission has been shown to be proportional to sunspot activity. However, the level of the sun's ultraviolet and X-ray emissions is primarily responsible for causing ionization in the earth's upper atmosphere. We now have data from the [[GOES]] spacecraft that measures the background '''X-ray flux''' from the sun, a parameter more closely related to the ionization levels in the ionosphere. * The ''[[A-index|A]]'' and ''[[K-index|K]]'' indices are a measurement of the behavior of the horizontal component of the '''geomagnetic field'''. The ''K'' index uses a scale from 0 to 9 to measure the change in the horizontal component of the geomagnetic field. A new ''K'' index is determined at the [[Table Mountain]] Observatory, north of [[Boulder, Colorado|Boulder]], [[Colorado]]. * The geomagnetic activity levels of the earth are measured by the fluctuation of the Earth's magnetic field in [[SI]] units called [[tesla (unit)]]s (or in non-SI [[gauss (unit)|gauss]], 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 ''ap'' index, called the ''planetary A-index'' (PAI). ===Scientific research on ionospheric propagation=== Scientists also are exploring the structure of the ionosphere by a wide variety of methods, including passive observations of optical and radio emissions generated in the ionosphere, bouncing radio waves of different frequencies from it, incoherent scatter radars such as the EISCAT, Sondre Stromfjord, Millstone Hill, Arecibo, and Jicamarca radars, coherent scatter radars such as the [[Super Dual Auroral Radar Network|Super Dual Auroral Radar Network (SuperDARN)]] radars, and using special receivers to detect how the reflected waves have changed from the transmitted waves. A variety of experiments, such as HAARP ([[High Frequency Active Auroral Research Program]]), 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. There is concern among many members of the scientific community regarding the dangers involved in disturbing the ionosphere. 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. The project involves more than 11 different countries and multiple radars in both hemispheres. Scientists are also examining the ionosphere by the changes to radio waves from satellites and stars passing through it. The [[Arecibo radio telescope]] located in [[Puerto Rico]], was originally intended to study Earth's ionosphere. ==History== In 1899, [[Nikola Tesla]] moved from New York to [[Colorado Springs, Colorado]], where he would have room for his high-voltage, high-frequency experiments. Upon his arrival he told reporters that he was conducting wireless telegraphy experiments transmitting signals from Pikes Peak to [[Paris]].<ref>[http://www.magnetricity.com/Tesla/Tesla_Biography.php Tesla biography at magnetricity.com]</ref> Tesla's diary contains explanations of his experiments concerning the ionosphere.<ref>Tesla, Nikola, "The True Wireless". ''Electrical Experimenter'', May 1919. ([http://www.pbs.org/tesla/res/res_art06.html also at pbs.org])</ref> [[Guglielmo Marconi]] received the first trans-Atlantic radio signal on [[December 12]], [[1901]], in [[St. John's, Newfoundland]] (now in [[Canada]]) using a 152.4 m (500 foot) kite-supported antenna for reception. The transmitting station in [[Poldhu]], Cornwall used a spark-gap transmitter to produce a signal with a frequency of approximately 500 [[Kilohertz|kHz]] and a power of 100 times more than any radio signal previously produced. The message received was three dots, the [[Morse code]] for the letter '''S'''. To reach Newfoundland the signal would have to bounce off the ionosphere twice. Dr. Jack Belrose has recently contested this, however, based on theoretical and experimental work.<ref>John S. Belrose, "[http://www.ieee.ca/millennium/radio/radio_differences.html Fessenden and Marconi: Their Differing Technologies and Transatlantic Experiments During the First Decade of this Century]". International Conference on 100 Years of Radio -- 5-7 September 1995.</ref> However, Marconi did achieve transatlantic wireless communications beyond a shadow of doubt in Glace Bay one year later. In 1902, [[Oliver Heaviside]] proposed the existence of the ''Kennelly-Heaviside Layer'' of the ionosphere which bears his name. Heaviside's proposal included means by which radio signals are transmitted around the Earth's curvature. Heaviside's proposal, coupled with Planck's law of black body radiation, may have hampered the growth of radio astronomy for the detection of electromagnetic waves from celestial bodies until 1932 (and the development of high frequency radio transceivers). Also in [[1902]], [[Arthur Edwin Kennelly]] discovered some of the ionosphere's radio-electrical properties. In 1912, the [[U.S. Congress]] imposed the [[Radio Act of 1912]] on amateur radio operators, 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. In 1926, Scottish physicist [[Robert Watson-Watt]] introduced the term ''ionosphere'' in a letter published only in 1969 in ''[[Nature (journal)|Nature]]'': {{Quotation|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 this series.}} [[Edward V. Appleton]] was awarded a [[Nobel Prize]] in 1947 for his confirmation in 1927 of the existence of the ionosphere. [[Lloyd Berkner]] first measured the height and density of the ionosphere. This permitted the first complete theory of short wave radio propagation. [[Maurice V. Wilkes]] and [[J. A. Ratcliffe]] researched the topic of radio propagation of very long radio waves in the ionosphere. [[Vitaly Ginzburg]] has developed a theory of electromagnetic wave propagation in plasmas such as the ionosphere. In 1962 the [[Canada|Canadian]] satellite [[Alouette 1]] was launched to study the ionosphere. Following its success were [[Alouette 2]] in 1965 and the two [[ISIS (satellite)|ISIS]] satellites in 1969 and 1971, all for measuring the ionosphere. ==References== {{reflist}} * Corum, J. F., and Corum, K. L., "''A Physical Interpretation of the Colorado Springs Data''". Proceedings of the Second International Tesla Symposium. Colorado Springs, Colorado, 1986. * Davies, K., 1990. Peter Peregrinus Ltd, London. ISBN 0-86341-186-X ''Ionospheric Radio''. * Grotz, Toby, "''The True Meaning of Wireless Transmission of power''". Tesla : A Journal of Modern Science, 1997. * Hargreaves, J. K., "''The Upper Atmosphere and Solar-Terrestrial Relations''". Cambridge University Press, 1992, * Kelley, M. C, and Heelis, R. A., "''The Earth's Ionosphere: Plasma Physics and Electrodynamics''". Academic Press, 1989. * Leo F. McNamara. (1994) ISBN 0-89464-804-7 ''Radio Amateurs Guide to the Ionosphere''. *{{cite journal | date=[[1 January]][[1986]] | author=K.Rawer and Y.V.Ramanamurty (eds) | title=International Reference Ionosphere - Status 1985/86 | journal=Advances in Space Research|volume=5|issue=10 | id=ISBN 0-08-034026-1 (Publisher: Pergamon Press), {{ISSN|0273-1177}} }} ==See also== * '''[[Geophysics]]''' ** [[Van Allen radiation belt]] * '''[[Radio]]''' ** [[Fading]] ** [[Line-of-sight propagation]] ** [[List of telecommunications transmission terms]] ** [[Ionospheric absorption]] * '''Related''' ** [[Tether propulsion]] ** [[Canadian Geospace Monitoring]] ** [[Pioneer Venus project]] ** [[Nozomi]] ** ''[[New Horizons]]'' ** [[Soft gamma repeater]] ** [[TIMED (Thermosphere Ionosphere Mesosphere Energetics and Dynamics)]] ** [[International Geophysical Year]] ** [[Lightning#Sprites, Elves, Jets and other Upper Atmospheric Lightning|Upper Atmospheric Lightning]] * '''Lists''' ** [[List of astronomical topics]] ** [[List of electronics topics]] ==External links== {{wiktionarypar|ionosphere}} {{refbegin}} * Gehred, Paul, and Norm Cohen, ''[http://www.sec.noaa.gov/radio SWPC's Radio User's Page]''. *[http://www.esa-spaceweather.net/sda/ionosfera/ Amsat-Italia project on Ionospheric propagation (ESA SWENET website)] *[http://www.kn4lf.com/kn4lf5.htm KN4LF Solar Space Weather & Geomagnetic Data Archive] *[http://www.kn4lf.com/kn4lf8.htm KN4LF 160 Meter Radio Propagation Theory Notes] Layman Level Explanations Of "Seemingly" Mysterious 160 Meter (MF/HF) Propagation Occurrences *[http://geomag.usgs.gov USGS Geomagnetism Program] *[http://www.britannica.com/eb/article-9042708/ionosphere-and-magnetosphere Encyclopaedia Britannica, Ionosphere and magnetosphere] *[http://www.sec.noaa.gov/SWN/ Current Space Weather Conditions] *[http://www.sec.noaa.gov/rt_plots/xray_1m.html Current Solar X-Ray Flux] *[http://superdarn.jhuapl.edu/ Super Dual Auroral Radar Network] *[http://www.eiscat.se/ European Inchorent Scatter radar system] *[http://haystack.mit.edu/atm/mho/index.html Millstone Hill incoherent scatter radar] <!-- *[http://www.kuittho.edu.my/waras Equatorial Ionosonde Station] --> {{refend}} {{earthsatmosphere}} [[Category:Radio frequency propagation]] [[Category:Nikola Tesla]] [[Category:Atmosphere]] [[Category:Space plasmas]] [[Category:Plasma physics]] [[Category:Radio terminology]] [[ar:أيونوسفير]] [[bs:Jonosfera]] [[bg:Йоносфера]] [[ca:Ionosfera]] [[cs:Ionosféra]] [[da:Ionosfære]] [[de:Ionosphäre]] [[el:Ιονόσφαιρα]] [[es:Ionosfera]] [[eo:Jonosfero]] [[fr:Ionosphère]] [[gl:Ionosfera]] [[ko:전리층]] [[hr:Ionosfera]] [[id:Ionosfer]] [[it:Ionosfera]] [[he:יונוספירה]] [[lv:Jonosfēra]] [[lt:Jonosfera]] [[mk:Јоносфера]] [[nl:Ionosfeer]] [[ja:電離層]] [[nn:Ionosfæren]] [[pl:Jonosfera]] [[pt:Ionosfera]] [[ru:Ионосфера]] [[sk:Ionosféra]] [[sr:Јоносфера]] [[fi:Ionosfääri]] [[sv:Jonosfär]] [[th:ไอโอโนสเฟียร์]] [[tr:İyonosfer]] [[uk:Іоносфера]] [[zh:电离层]]