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Title: Stabilization of the fan instability: Electron flux relaxation

Abstract

This paper presents some relevant simulation results on the interaction between electrostatic waves and suprathermal electron fluxes at anomalous cyclotron and Landau resonances. In particular, the case of a dense and continuous wave spectrum is studied. It is shown that, after the waves excited by the fan instability at anomalous cyclotron resonances have reached a first saturation stage due to particle trapping, the process of 'dynamical resonance merging' takes place, which leads to a strong amplification of the waves' amplitudes. The Landau resonances do not play an essential role in the total energy exchange between the particles and the waves, as they mainly help to smooth the peaks rising during the evolution of the electron parallel velocity distribution and contribute to damping. Moreover, the paper shows that at the asymptotic stage of the interaction, when the waves' amplitudes are saturated and the electron flux is relaxed, some physical features clearly do not fit the predictions of the well-known quasilinear theory. The careful examination of a huge number of trajectories of particles moving in the effective field of the wave packet allows to state that most of the particles involved in the resonant interactions are trapped by several waves simultaneously. Inmore » this so-called 'multitrapping' process, the particles perform complex oscillatory motions which are far from what is expected from the quasilinear theory, where the diffusive behavior of the particles in the velocity space results from small successive random steps.« less

Authors:
;  [1];  [2]
  1. Laboratoire de Physique des Gaz et des Plasmas, Universite Paris Sud, 91405 Orsay Cedex (France)
  2. (IKI) 117997, 84/32 Profsoyuznaya Str., Moscow (Russian Federation)
Publication Date:
OSTI Identifier:
20860425
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 13; Journal Issue: 12; Other Information: DOI: 10.1063/1.2372464; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; AMPLITUDES; BEAM-PLASMA SYSTEMS; CYCLOTRON RESONANCE; DAMPING; DISTRIBUTION; ELECTRON BEAMS; ELECTRONS; ENERGY TRANSFER; PLASMA; PLASMA INSTABILITY; PLASMA SIMULATION; PLASMA WAVES; QUASILINEAR PROBLEMS; RADIATION TRANSPORT; RELAXATION; STABILIZATION; TRAPPING; VELOCITY; WAVE PACKETS

Citation Formats

Krafft, C., Volokitin, A., and Space Research Institute. Stabilization of the fan instability: Electron flux relaxation. United States: N. p., 2006. Web. doi:10.1063/1.2372464.
Krafft, C., Volokitin, A., & Space Research Institute. Stabilization of the fan instability: Electron flux relaxation. United States. doi:10.1063/1.2372464.
Krafft, C., Volokitin, A., and Space Research Institute. Fri . "Stabilization of the fan instability: Electron flux relaxation". United States. doi:10.1063/1.2372464.
@article{osti_20860425,
title = {Stabilization of the fan instability: Electron flux relaxation},
author = {Krafft, C. and Volokitin, A. and Space Research Institute},
abstractNote = {This paper presents some relevant simulation results on the interaction between electrostatic waves and suprathermal electron fluxes at anomalous cyclotron and Landau resonances. In particular, the case of a dense and continuous wave spectrum is studied. It is shown that, after the waves excited by the fan instability at anomalous cyclotron resonances have reached a first saturation stage due to particle trapping, the process of 'dynamical resonance merging' takes place, which leads to a strong amplification of the waves' amplitudes. The Landau resonances do not play an essential role in the total energy exchange between the particles and the waves, as they mainly help to smooth the peaks rising during the evolution of the electron parallel velocity distribution and contribute to damping. Moreover, the paper shows that at the asymptotic stage of the interaction, when the waves' amplitudes are saturated and the electron flux is relaxed, some physical features clearly do not fit the predictions of the well-known quasilinear theory. The careful examination of a huge number of trajectories of particles moving in the effective field of the wave packet allows to state that most of the particles involved in the resonant interactions are trapped by several waves simultaneously. In this so-called 'multitrapping' process, the particles perform complex oscillatory motions which are far from what is expected from the quasilinear theory, where the diffusive behavior of the particles in the velocity space results from small successive random steps.},
doi = {10.1063/1.2372464},
journal = {Physics of Plasmas},
number = 12,
volume = 13,
place = {United States},
year = {Fri Dec 15 00:00:00 EST 2006},
month = {Fri Dec 15 00:00:00 EST 2006}
}