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

Chang, Sue-min; Ni, Binbin; Bortnik, J.; Zhou, Chen; Zhao, Zhengyu; Li, Jinxing; Gu, Xudong

doi:10.5194/angeo-32-507-2014

Cited by 9 publications

(9 citation statements)

References 38 publications

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“…We can find that unlike the field‐aligned waves, the profile of diffusion rates of highly oblique waves is very unsmooth, with some pronounced nulls, such as 30°–35°. Actually, this feature has been captured in some previous works regarding to highly oblique waves (Bortnik & Thorne, ; Chang et al, ). Beyond that, Figure shows that the highly oblique monotonic waves can drive pitch angle scattering of 300‐keV electrons with a rate of ~10 −6 /s at low equatorial pitch angles near the loss cone, which is similar to that of field‐aligned monotonic wave in Figure .…”

Section: The Simulation Resultsmentioning

confidence: 80%

Energetic Electron Diffusion by Modulated Heating of the Ionosphere

Chang

Cao

et al. 2018

JGR Space Physics

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Aiming to assess the effect on the radiation belts due to modulated heating of the ionosphere, this study adopts the test particle simulation to investigate the resonant interaction between energetic electron and the heater‐induced monotonic ELF/VLF (extremely low frequency/very low frequency) waves, with wave distribution obtained by DEMETER observations and numerical computation. It is found that while energy diffusion is weak, pitch angle scattering on energetic electrons can be intense at low equatorial pitch angles near the loss cone for both field‐aligned monotonic waves generated by high‐latitude heater and highly oblique monotonic waves generated by low‐latitude heater. Our investigation supports the feasibility of modulated heating of both high‐latitude ionosphere and low‐latitude ionosphere for controlled precipitation of energetic electron but also suggests that electron diffusion of field‐aligned monotonic waves is more effective, as the diffusion rates can be larger for lower energy electron or at higher equatorial pitch angles and do not vary much with the modulated frequency. Finally, the results are compared with the quasi‐linear theory. Though the test particle diffusion coefficients are in good agreement with the quasi‐linear diffusion coefficients for field‐aligned monotonic waves, they are in very limited agreement for highly oblique monotonic waves, which bring into question the applicability of quasi‐linear theory to monotonic highly oblique wave.

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Section: The Simulation Resultsmentioning

confidence: 80%

Energetic Electron Diffusion by Modulated Heating of the Ionosphere

Chang

Cao

et al. 2018

JGR Space Physics

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“…This signal excites a VLF whistler mode resonator supported by amplification by cyclotron resonance with radiation belt particles trapped on the magnetic field lines (Figure 18). The energy of the resonant particles is computed from the cyclotron resonance formula (Chang et al., 2014; Sa, 1989).

\frac{\partial θ}{\partial t} = - k_{1} v_{∥} - ω_{1} + ω_{c e} where ω_{c e} = \frac{e B_{0}}{m_{e}}, E_{e ∥} = \frac{1}{2} m_{e} v_{∥}^{2} .

…”

Section: Whistler Mode Propagation In the Magneto‐plasmamentioning

confidence: 99%

Strong Amplification of ELF/VLF Signals in Space Using Neutral Gas Injections From a Satellite Rocket Engine

et al. 2021

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The first demonstration of rocket exhaust driven amplification (REDA) of whistler mode waves occurred on May 26, 2020 by transferring energy from pickup ions in a rocket exhaust plume to EM waves. The source of coherent VLF waves was the Navy NML Transmitter at 25.2 kHz located in LaMoure, North Dakota. The topside ionosphere at 480 km altitude became an amplifying medium with a 60 s firing of the Cygnus BT‐4 engine. The rocket engine injected exhaust as a neutral cloud moving perpendicular to field lines that connected the NML transmitter to the VLF Radio Receiver Instrument (RRI) on e‐POP/SWARM‐E. Charge exchange between the ambient O+ ions and the hypersonic water molecules in the exhaust produced H2O+ ions in a ring‐beam velocity distribution. The 25.2 kHz VLF signal from NML was amplified by 30 dB for a period 77 s as observed by the RRI. Simultaneously, preexisting coherent ELF waves at 300 Hz were amplified by 50 dB during and after the Cygnus burn. Extremely strong coherent emissions and quasiperiodic bursts in the 300–310 Hz frequency range lasted for 200 s after the release. The excitation of an ELF whistler cavity may have lasted even longer, but the orbit of the SWARM‐E/e‐POP moved the RRI sensor away from the wave emission region. The amplified 300 Hz ELF waves may have gained even more energy by cyclotron resonance with radiation belt electrons as they were ducted between geomagnetic‐conjugate hemispheres.

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“…Typically, only the n = 0, ±1, ±2 resonances need to be considered for Whistler waves; however, sufficiently high-energy electrons may have access to the higher-order resonances (Chang et al 2014). Equation (2.23) may, alternatively, be expressed as: where r rel.…”

Section: Transport Via Magnetic Pitch-angle Diffusionmentioning

confidence: 99%

Diffusion and radiation in magnetized collisionless plasmas with small-scale Whistler turbulence

Keenan¹,

Medvedev²

2016

J. Plasma Phys.

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Magnetized high-energy-density plasmas can often have strong electromagnetic fluctuations whose correlation scale is smaller than the electron Larmor radius. Radiation from the electrons in such plasmas -which markedly differs from both synchrotron and cyclotron radiation -is tightly related to their energy and pitch-angle diffusion. In this paper, we present a comprehensive theoretical and numerical study of particle transport in cold, 'small-scale' Whistler-mode turbulence and its relation to the spectra of radiation simultaneously produced by these particles. We emphasize that this relation is a superb diagnostic tool of laboratory, astrophysical, interplanetary and solar plasmas with a mean magnetic field and strong small-scale turbulence.

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

Cited by 9 publications

References 38 publications

Energetic Electron Diffusion by Modulated Heating of the Ionosphere

Energetic Electron Diffusion by Modulated Heating of the Ionosphere

Strong Amplification of ELF/VLF Signals in Space Using Neutral Gas Injections From a Satellite Rocket Engine

Diffusion and radiation in magnetized collisionless plasmas with small-scale Whistler turbulence

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