TY - JOUR
T1 - An obliquely propagating electromagnetic drift instability in the lower hybrid freauency range
AU - Ji, Hantao
AU - Kulsrud, Russell
AU - Fox, William
AU - Yamada, Masaaki
N1 - Copyright:
Copyright 2015 Elsevier B.V., All rights reserved.
PY - 2005/8
Y1 - 2005/8
N2 - By employing a local two-fluid theory, we investigate an obliquely propagating electromagnetic instability in the lower hybrid frequency range driven by cross-field current or relative drifts between electrons and ions. The theory self-cpnsistently takes into account local cross-field current and accompanying pressure gradients. It is found that the instability is caused by reactive coupling between the backward propagating whistler (fast) wave in the electron frame and the forward propagating sound (slow) wave in the ion frame when the relative drifts are large. The unstable waves we consider propagate obliquely to the unperturbed magnetic field and have mixed polarization with significant electromagnetic components. A physical picture of the instability emerges in the limit of a large wave number characteristic of the local approximation. The primary positive feedback mechanism is based on reinforcement of initial electron density perturbations by compression of electron fluid via induced Lorentz force. The resultant waves are qualitatively consistent with the measured electromagnetic fluctuations in reconnecting current sheet in a laboratory plasma.
AB - By employing a local two-fluid theory, we investigate an obliquely propagating electromagnetic instability in the lower hybrid frequency range driven by cross-field current or relative drifts between electrons and ions. The theory self-cpnsistently takes into account local cross-field current and accompanying pressure gradients. It is found that the instability is caused by reactive coupling between the backward propagating whistler (fast) wave in the electron frame and the forward propagating sound (slow) wave in the ion frame when the relative drifts are large. The unstable waves we consider propagate obliquely to the unperturbed magnetic field and have mixed polarization with significant electromagnetic components. A physical picture of the instability emerges in the limit of a large wave number characteristic of the local approximation. The primary positive feedback mechanism is based on reinforcement of initial electron density perturbations by compression of electron fluid via induced Lorentz force. The resultant waves are qualitatively consistent with the measured electromagnetic fluctuations in reconnecting current sheet in a laboratory plasma.
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U2 - 10.1029/2005JA011188
DO - 10.1029/2005JA011188
M3 - Article
AN - SCOPUS:33746361463
VL - 110
JO - Journal of Geophysical Research: Space Physics
JF - Journal of Geophysical Research: Space Physics
SN - 2169-9402
IS - A8
M1 - A08212
ER -