Characteristics of ionospheric ELF radiation generated by HF heating

Ferraro, Anthony J.; Lee, H.S; Allshouse, Roger; Carroll, K.; Lunnen, R. J.; Collins, T. W.

doi:10.1016/0021-9169(84)90025-4

Cited by 51 publications

(26 citation statements)

References 7 publications

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“…Since then, this facility has been used by many investigators and some examples of results include: HF enhanced plasma lines (HFPL) observed in the E-and F-regions (Wong and Taylor 1971;Carlson et al 1972;Kantor 1974;Carlson and Duncan 1977;Muldrew and Showen 1977;Muldrew 1978;Showen and Kim 1978;Djuth 1984, and Djuth et al 1986). ELF radiation from the ionospheric current system modified by the HF heater was also demonstrated at Arecibo by Ferraro et al (1984).…”

Section: The Low-latitude Hf Heating Facility At the National Aeronommentioning

confidence: 91%

Radio Techniques for Probing the Terrestrial Ionosphere

Hunsucker¹

1991

Physics and Chemistry in Space

101

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Section: The Low-latitude Hf Heating Facility At the National Aeronommentioning

confidence: 91%

Radio Techniques for Probing the Terrestrial Ionosphere

Hunsucker¹

1991

Physics and Chemistry in Space

101

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“…With the development of space technology, the US and Russia started testing to transmit VLF/SLF waves from small satellites on low Earth orbit (LEO) (Armand et al 1988;Bannister et al 1993). Additionally, VLF/SLF/ELF electromagnetic radiation can also be generated by high-frequency heating (Ferraro et al 1984;Lunnen 1985;Barr et al 1987Barr et al , 1988. In summer 1992, a joint experiment by NASA and Italian Space Agency (ASI) was carried out on board space shuttle "Atlantis" to deploy a tethered satellite, which includes a 20 km conducting tether and a 23 kg payload.…”

Section: Vlf/slf/elf Field On Sea Surface Excited By Space Borne Tranmentioning

confidence: 99%

Historical and Technical Overview of SLF/ELF Electromagnetic Wave Propagation

Pan¹,

Li²

2013

Advanced Topics in Science and Technology in China

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In general, very low frequency (VLF) refers to electromagnetic waves with frequencies from 3 kHz to 30 kHz; ultra low frequency (ULF) refers to frequency range between 300 Hz to 3 kHz; the frequency range of 30 Hz to 300 Hz is defined as super low frequency (SLF); and the frequency below 30 Hz is referred to as extremely low frequency (ELF). In some early studies, alternative definitions may have been used with frequency range of 3 Hz to 3 kHz generally referred to ELF. In this book, the emphasis is on SLF (30-300 Hz) and ELF (below 30 Hz) ranges, using the MKS system of units and the time dependency e −iωt . Medium Characteristics of SLF/ELF Wave PropagationDue to the long wavelength, SLF/ELF waves, when excited and propagated on and near the Earth's surface, will cover lithosphere, atmosphere and ionosphere, whose electromagnetic characteristics differ significantly in their propagation paths. The permeability of the atmosphere and ionosphere is approximately μ 0 , the permeability in free space, as well as that of the lithosphere, except in the regions that are rich in iron, nickel, cobalt, etc. Therefore, the permeability of the lithosphere can be also treated as μ 0 , if neither the transmitter nor the receiver is located in mineral-rich areas. The atmosphere is a non-conductive medium with negligible conductivity, whose permittivity is close to ε 0 , the permittivity of free space. While the lithosphere is conductive, the conductivity of sea water σ sea is in the range of 2.5-5.5 S/m, and the conductivity σ g of rock and soil in the range of 10 −2 -10 −4 S/m. The dielectric constant ε r of the lithosphere does not have large effects on the propagation of SLF/ELF waves.The ionosphere is composed of partially ionized gas, which includes electrons, ions, and electrically neutral particles, above 70 km or so from the sea level. The electrons and ions make the ionosphere conductive, thus the majority of the energy of the incident VLF/SLF/ELF waves will be reflected by the ionosphere. When both the transmitter and the receiver are located in the space between the ground and the W. Pan, K. Li, Propagation of SLF/ELF Electromagnetic Waves,

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“…The induced alternating current (AC) in the electrojet is then the antenna current for VLF radiation at the modulation frequency and its harmonics. Generation of VLF waves in the high latitude ionosphere via electrojet modulation has been studied experimentally [1][2][3][4][5][6][7][8][9][10][11][12][13] and theoretically. [12][13][14][15][16][17][18][19][20][21][22] The heating and cooling rates as well as the available heating and cooling times in one modulation period affect the efficacy of conductivity modulation by an intensity modulated HF heater.…”

Section: Introductionmentioning

confidence: 99%

Ionospheric very low frequency transmitter

Kuo

2015

Physics of Plasmas

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The theme of this paper is to establish a reliable ionospheric very low frequency (VLF) transmitter, which is also broad band. Two approaches are studied that generate VLF waves in the ionosphere. The first, classic approach employs a ground-based HF heater to directly modulate the high latitude ionospheric, or auroral electrojet. In the classic approach, the intensity-modulated HF heater induces an alternating current in the electrojet, which serves as a virtual antenna to transmit VLF waves. The spatial and temporal variations of the electrojet impact the reliability of the classic approach. The second, beat-wave approach also employs a ground-based HF heater; however, in this approach, the heater operates in a continuous wave mode at two HF frequencies separated by the desired VLF frequency. Theories for both approaches are formulated, calculations performed with numerical model simulations, and the calculations are compared to experimental results. Theory for the classic approach shows that an HF heater wave, intensity-modulated at VLF, modulates the electron temperature dependent electrical conductivity of the ionospheric electrojet, which, in turn, induces an ac electrojet current. Thus, the electrojet becomes a virtual VLF antenna. The numerical results show that the radiation intensity of the modulated electrojet decreases with an increase in VLF radiation frequency. Theory for the beat wave approach shows that the VLF radiation intensity depends upon the HF heater intensity rather than the electrojet strength, and yet this approach can also modulate the electrojet when present. HF heater experiments were conducted for both the intensity modulated and beat wave approaches. VLF radiations were generated and the experimental results confirm the numerical simulations. Theory and experimental results both show that in the absence of the electrojet, VLF radiation from the F-region is generated via the beat wave approach. Additionally, the beat wave approach generates VLF radiations over a larger frequency band than by the modulated electrojet. V C 2015 AIP Publishing LLC.

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Characteristics of ionospheric ELF radiation generated by HF heating

Cited by 51 publications

References 7 publications

Radio Techniques for Probing the Terrestrial Ionosphere

Radio Techniques for Probing the Terrestrial Ionosphere

Historical and Technical Overview of SLF/ELF Electromagnetic Wave Propagation

Ionospheric very low frequency transmitter

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