Detection of local and long‐path VLF/ELF radiation from modulated ionospheric current systems

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

doi:10.1029/rs020i003p00553

Cited by 12 publications

(5 citation statements)

References 7 publications

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“…The only other published measurements of far field data from modulated heating experiments were made by Ferraro et al [1982], who claimed that signals at 2.073 kHz from the PEJ antenna at RamOord were detected with reasonable certainty in the United States at a range of 6000 kin, and by Lunnen et al [1984], who claimed to have detected signals at 2.5 kHz in Puerto Rico at a range of 3532 km from a modulated equatorial electrojet above Jicamarca, Peru. Recently, Lunnen et al [1985] reported signals from the modulated dynamo current above Arecibo, Puerto Rico,' observed at various ranges less than 1000 km on board a ship and at Pennsylvania (2707 km). We compare some of these claims with extrapolations of our results to such long distances.…”

Section: Comparison With Other Experimentsmentioning

confidence: 99%

ELF and VLF signals radiated by the “polar electrojet antenna”: Experimental results

Barr¹,

Stubbe

Rietveld

et al. 1986

J. Geophys. Res.

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The heating facility at Ramfjordmoen near Tromsø, Norway, has been used to modulate the auroral electrojet at frequencies in the range 223 Hz to 5.44 kHz. ELF/VLF signals have been received at Lycksele, Sweden, 554 km from the heating transmitter, over the whole frequency range with maximum amplitudes of ∼50 fT. Both azimuthal and radial magnetic field components were recorded and the ratio of these two components, commonly termed the polarization, was determined. The experimental results have been successfully modelled by using waveguide mode theory and assuming the heating source to be a point dipole located in the ionosphere at the height of the maximum ELF/VLF Hall current.

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Section: Comparison With Other Experimentsmentioning

confidence: 99%

ELF and VLF signals radiated by the “polar electrojet antenna”: Experimental results

Barr¹,

Stubbe

Rietveld

et al. 1986

J. Geophys. Res.

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“…The techniques used can generally be split into two distinct groups: those which rely on ionospheric conductivity modulation in the presence of an ambient current system in the ionosphere [Kapustin et al, 1977;Stubbe and Kopka, 1977;Ferraro et al, 1982] and those which rely on nonlinear wave interactions [Papadopoulos et al, 1983;Papadopoulos and Chanq, 1985]. The generation of ELF/VLF waves using the former mechanism has been confirmed at both auroral and equatorial latitudes [Kapustin et al, 1977;Stubbe et al, 1981;Lunnen et al, 1985], and recently Ganguly [1986] has detected ULF waves at Are½ibo which could possibly be explained by the theories of Papadopoulos et al [1983]. The work to be described here is concerned with ELF/VLF wave generation by modulation of ionospheric conductivity.…”

Section: Introductionmentioning

confidence: 99%

Ionospheric heater beam scanning: A realistic model of this mobile source of ELF/VLF radiation

Barr¹,

Rietveld

Stubbe

et al. 1988

Radio Science

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The generation of ELF/VLF radio waves by heating the auroral ionosphere with a powerful HF transmitter, modulated at the ELF/VLF frequency, is now well documented. Recently, results were presented of the phase of the ELF/VLF signals received at a distance of 500 km from such a source as the HF beam was deflected toward and away from the receiver by up to 37° from the vertical. The phase data were modeled assuming the source to be a simple point dipole located in the ionosphere at the point of maximum HF radiation. This simple model provided good agreement with experimental phase data only when the HF beam was deflected toward the ELF/VLF receiver. The model of the ELF/VLF generation mechanism presented here includes contributions from the majority of the HF radiation pattern illuminating the ionosphere and assumes it to be a continuous source of ELF/VLF excitation. Computations based on this new model provide excellent agreement with the experimental phase data at all beam deflection angles. The use of this model to improve the power efficiency of the generation of ELF/VLF radio waves by HF heating facilities by more than a factor of 3 is discussed.

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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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Detection of local and long‐path VLF/ELF radiation from modulated ionospheric current systems

Cited by 12 publications

References 7 publications

ELF and VLF signals radiated by the “polar electrojet antenna”: Experimental results

ELF and VLF signals radiated by the “polar electrojet antenna”: Experimental results

Ionospheric heater beam scanning: A realistic model of this mobile source of ELF/VLF radiation

Historical and Technical Overview of SLF/ELF Electromagnetic Wave Propagation

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