VLF/ELF radiation from the ionospheric dynamo current system modulated by powerful HF signals

Ferraro, Anthony J.; Lee, H. S.; Allshouse, Roger; Carroll, K.; Tomko, A. A.; Kelly, F. J.; Joiner, R. G.

doi:10.1016/0021-9169(82)90022-8

Cited by 78 publications

(46 citation statements)

References 3 publications

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“…A significant body of data from ground VLF observations at different heating facilities has been used to establish the characteristics of downward radiation from the auroral radiator (Kapustin et al, 1977;Stubbe et al, 1981Stubbe et al, , 1982Ferraro et al, 1982; The dashed line rectangles indicate the regions where the HAARP signal was detected for the two successful passes. All the trajectories were in the south-to-north direction.…”

Section: Introductionmentioning

confidence: 99%

Cluster observations of ELF/VLF signals generated by modulated heating of the lower ionosphere with the HAARP HF transmitter

et al. 2004

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Abstract.It is now well known that amplitude modulated HF transmissions into the ionosphere can be used to generate ELF/VLF signals using the so-called "electrojet antenna". Although most observations of the generated ELF/VLF signals have been made on the ground, several low and highaltitude satellite observations have also been reported (James et al., 1990). One of the important unknowns in the physics of ELF/VLF wave generation by ionospheric heating is the volume of the magnetosphere illuminated by the ELF/VLF waves. In an attempt to investigate this question further, ground-satellite conjunction experiments have recently been conducted using the four Cluster satellites and the HF heater of the High-Frequency Active Auroral Research Program (HAARP) facility in Gakona, Alaska. Being located on largely closed field lines at L≈4.9, HAARP is currently also being used for ground-to-ground type of ELF/VLF waveinjection experiments, and will be increasingly used for this purpose as it is now being upgraded for higher power operation. In this paper, we describe the HAARP installation and present recent results of the HAARP-Cluster experiments. We give an overview of the detected ELF/VLF signals at Cluster, and a possible explanation of the spectral signature detected, as well as the determination of the location of the point of injection of the HAARP ELF/VLF signals into the magnetosphere using ray tracing.

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Section: Introductionmentioning

confidence: 99%

Cluster observations of ELF/VLF signals generated by modulated heating of the lower ionosphere with the HAARP HF transmitter

et al. 2004

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“…1, when ELF/VLF waves are generated as a result of periodic modulation of the ionospheric currents by HF heating (Ferraro et al, 1982;Barr and Stubbe, 1991;Inan et al, 2004;Platino et al, 2006;Piddyachiy et al, 2008), some waves propagate directly upwards and others propagate within the Earth-ionosphere waveguide and leak up progressively with each reflection off the ionosphere (James et al, 1984;Inan et al, 2004;Platino et al, 2006;Piddyachiy et al, 2008). Subsequently, these leaked waves propagate outwards and encounter energetic electrons that can potentially undergo resonant wave-particle interactions.…”

Section: Ray Tracing Simulations Of Elf/vlf Waves Generated By Modulamentioning

confidence: 99%

“…Here, we select waves at four frequencies, 0.5, 1, 2, and 4 kHz, which are within the general frequency band associated with the HF modulated heating facilities (e.g., Ferraro et al, 1982;Barr and Stubbe, 1991;Platino et al, 2006;Piddyachiy et al, 2008). We also perform the ray tracing starting at two latitudes, 15 • (black curves) and 25 • (red curves), focusing on ELF/VLF whistler wave triggering at low latitudes (Ferraro et al, 1982). By doing so, we can investigate the dependence of wave propagation path on both wave frequency and initial launch latitude.…”

Section: Ray Tracing Simulations Of Elf/vlf Waves Generated By Modulamentioning

confidence: 99%

“…Generation of extremely low-frequency (ELF)/very lowfrequency (VLF) waves by modulated heating of the D region ionosphere in the presence of naturally forming ionospheric currents is by now a well-established technique (e.g., Ferraro et al, 1982;Barr and Stubbe, 1991;Inan et al, 2004;Platino et al, 2006;Piddyachiy et al, 2008;and references therein). Periodic heating of the ionospheric region with a high-frequency (HF) transmitter modulates the conductivity of the region and, in turn, modulates these naturally forming (and pre-existing) currents, constituting what amounts to a giant radiating antenna at ∼ 60-100 km altitude.…”

Section: Introductionmentioning

confidence: 99%

“…Periodic heating of the ionospheric region with a high-frequency (HF) transmitter modulates the conductivity of the region and, in turn, modulates these naturally forming (and pre-existing) currents, constituting what amounts to a giant radiating antenna at ∼ 60-100 km altitude. The natural current system can be the auroral electrojet modulated by High-Power Auroral Stimulation (HIPAS) or HighFrequency Active Auroral Research Program (HAARP) heating facilities Platino et al, 2006;Piddyachiy et al, 2008), or the equatorial dynamo current modulated by the Arecibo heating facilities (Ferraro et al, 1982).…”

Section: Introductionmentioning

confidence: 99%

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Resonant scattering of energetic electrons in the plasmasphere by monotonic whistler-mode waves artificially generated by ionospheric modification

Chang

Bortnik

et al. 2014

Ann. Geophys.

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Abstract. Modulated high-frequency (HF) heating of the ionosphere provides a feasible means of artificially generating extremely low-frequency (ELF)/very low-frequency (VLF) whistler waves, which can leak into the inner magnetosphere and contribute to resonant interactions with highenergy electrons in the plasmasphere. By ray tracing the magnetospheric propagation of ELF/VLF emissions artificially generated at low-invariant latitudes, we evaluate the relativistic electron resonant energies along the ray paths and show that propagating artificial ELF/VLF waves can resonate with electrons from ∼ 100 keV to ∼ 10 MeV. We further implement test particle simulations to investigate the effects of resonant scattering of energetic electrons due to triggered monotonic/single-frequency ELF/VLF waves. The results indicate that within the period of a resonance timescale, changes in electron pitch angle and kinetic energy are stochastic, and the overall effect is cumulative, that is, the changes averaged over all test electrons increase monotonically with time. The localized rates of wave-induced pitch-angle scattering and momentum diffusion in the plasmasphere are analyzed in detail for artificially generated ELF/VLF whistlers with an observable in situ amplitude of ∼ 10 pT. While the local momentum diffusion of relativistic electrons is small, with a rate of < 10 −7 s −1 , the local pitchangle scattering can be intense near the loss cone with a rate of ∼ 10 −4 s −1 . Our investigation further supports the feasibility of artificial triggering of ELF/VLF whistler waves for removal of high-energy electrons at lower L shells within the plasmasphere. Moreover, our test particle simulation results show quantitatively good agreement with quasi-linear diffusion coefficients, confirming the applicability of both methods to evaluate the resonant diffusion effect of artificial generated ELF/VLF whistlers.

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Features of amplitude and Doppler frequency variation of ELF/VLF waves generated by “beat‐wave” HF heating at high latitudes

Tereshchenko

Шумилов

Касаткина

et al. 2014

Geophysical Research Letters

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Observations of extremely low frequency (ELF, 3-3000 Hz) radio waves generated by a "beat-wave" (BW) high frequency (~4.04-4.9 MHz) ionospheric heating are presented. ELF waves were registered with the ELF receiver located at Lovozero (68°N, 35°E), 660 km east from the European Incoherent Scatter Tromso heating facility (69. 6°N, 19.2°E). Frequency shifts between the generated beat-wave and received ELF waves were detected in all sessions. It is shown that the amplitudes of ELF waves depend on the auroral electrojet current strength. Our results showing a strong dependence of ELF signal intensities on the substorm development seem to support the conclusion that electrojet currents may affect the BW generation of ELF/VLF waves.

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VLF/ELF radiation from the ionospheric dynamo current system modulated by powerful HF signals

Cited by 78 publications

References 3 publications

Cluster observations of ELF/VLF signals generated by modulated heating of the lower ionosphere with the HAARP HF transmitter

Cluster observations of ELF/VLF signals generated by modulated heating of the lower ionosphere with the HAARP HF transmitter

Resonant scattering of energetic electrons in the plasmasphere by monotonic whistler-mode waves artificially generated by ionospheric modification

Features of amplitude and Doppler frequency variation of ELF/VLF waves generated by “beat‐wave” HF heating at high latitudes

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