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Title: Alfvenic phenomena triggered by resonant absorption of an O-mode pulse

Abstract

A simulation and modeling study is made of the nonlinear interaction of an electromagnetic pulse, in the O-mode polarization, with a magnetized plasma having a cross-field density gradient. For small amplitudes, the pulse propagates up to the cutoff layer where an Airy pattern develops. Beyond a certain power level, the ponderomotive force produced by the standing electromagnetic fields carves density cavities. The excess density piled up on the side of the cavities causes secondary, field-aligned plasma resonances to arise. Strong electron acceleration occurs due to the short scale of the secondary resonant fields. The fast electrons exiting the new resonant layers induce a return current system in the background plasma. This generates a packet of shear Alfven waves of small transverse scale and increasing frequency. The results provide insight into microscopic processes associated with a recent laboratory investigation in which large-amplitude Alfven waves have been generated upon application of high-power microwaves [B. Van Compernolle et al., Phys. Plasmas 13, 092112 (2006)].

Authors:
; ;  [1]
  1. Department of Physics and Astronomy, University of California, Los Angeles, California 90095 (United States)
Publication Date:
OSTI Identifier:
20974913
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 14; Journal Issue: 4; Other Information: DOI: 10.1063/1.2711428; (c) 2007 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; ABSORPTION; ACCELERATION; ALFVEN WAVES; AMPLITUDES; ELECTROMAGNETIC FIELDS; ELECTROMAGNETIC PULSES; ELECTRONS; INTERACTIONS; LAYERS; MICROWAVE RADIATION; NONLINEAR PROBLEMS; PLASMA; PLASMA DENSITY; PLASMA SIMULATION; POLARIZATION; PONDEROMOTIVE FORCE

Citation Formats

Tsung, F. S., Morales, G. J., and Tonge, J.. Alfvenic phenomena triggered by resonant absorption of an O-mode pulse. United States: N. p., 2007. Web. doi:10.1063/1.2711428.
Tsung, F. S., Morales, G. J., & Tonge, J.. Alfvenic phenomena triggered by resonant absorption of an O-mode pulse. United States. doi:10.1063/1.2711428.
Tsung, F. S., Morales, G. J., and Tonge, J.. Sun . "Alfvenic phenomena triggered by resonant absorption of an O-mode pulse". United States. doi:10.1063/1.2711428.
@article{osti_20974913,
title = {Alfvenic phenomena triggered by resonant absorption of an O-mode pulse},
author = {Tsung, F. S. and Morales, G. J. and Tonge, J.},
abstractNote = {A simulation and modeling study is made of the nonlinear interaction of an electromagnetic pulse, in the O-mode polarization, with a magnetized plasma having a cross-field density gradient. For small amplitudes, the pulse propagates up to the cutoff layer where an Airy pattern develops. Beyond a certain power level, the ponderomotive force produced by the standing electromagnetic fields carves density cavities. The excess density piled up on the side of the cavities causes secondary, field-aligned plasma resonances to arise. Strong electron acceleration occurs due to the short scale of the secondary resonant fields. The fast electrons exiting the new resonant layers induce a return current system in the background plasma. This generates a packet of shear Alfven waves of small transverse scale and increasing frequency. The results provide insight into microscopic processes associated with a recent laboratory investigation in which large-amplitude Alfven waves have been generated upon application of high-power microwaves [B. Van Compernolle et al., Phys. Plasmas 13, 092112 (2006)].},
doi = {10.1063/1.2711428},
journal = {Physics of Plasmas},
number = 4,
volume = 14,
place = {United States},
year = {Sun Apr 15 00:00:00 EDT 2007},
month = {Sun Apr 15 00:00:00 EDT 2007}
}