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Title: Experimental study of fluctuations excited by a narrow temperature filament in a magnetized plasma

Abstract

A systematic study is made of the spontaneous growth of fluctuations in temperature, density, and magnetic field in a narrow (on the order of the electron skin depth) field-aligned temperature filament embedded in a large magnetized plasma. Two broad classes of fluctuation (''low'' and ''high'' frequency modes) have been identified and studied in detail. A high-frequency drift-Alfven mode grows at frequencies about one tenth the ion gyrofrequency in the region of the filament where the temperature gradient is large. The measured radial profiles of the density and magnetic field fluctuations associated with this mode agree well with theoretical predictions. The high-frequency mode has been observed to exhibit several interesting nonlinear features, including steepening wave form, progression in azimuthal mode number, coupling to the low frequency mode with subsequent sideband generation, and eventually a transition to broad band turbulence. The nature of the low-frequency mode which has frequencies about one fiftieth of the ion gyrofrequency is less certain, but it has been identified as a spatially localized, azimuthally symmetric mode consisting primarily of temperature fluctuations. Both the high and low-frequency modes give rise to electron heat transport at rates in excess of the classical values. (c) 2000 American Institute of Physics.

Authors:
 [1];  [1];  [1]
  1. Department of Physics and Astronomy, University of California, Los Angeles, California 90095 (United States)
Publication Date:
OSTI Identifier:
20216029
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 7; Journal Issue: 5; Other Information: PBD: May 2000; Journal ID: ISSN 1070-664X
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; FLUCTUATIONS; PLASMA DENSITY; PLASMA FILAMENT; MAGNETIC FIELDS; ALFVEN WAVES; PLASMA HEATING; EXPERIMENTAL DATA; THEORETICAL DATA

Citation Formats

Burke, A. T., Maggs, J. E., and Morales, G. J. Experimental study of fluctuations excited by a narrow temperature filament in a magnetized plasma. United States: N. p., 2000. Web. doi:10.1063/1.873957.
Burke, A. T., Maggs, J. E., & Morales, G. J. Experimental study of fluctuations excited by a narrow temperature filament in a magnetized plasma. United States. doi:10.1063/1.873957.
Burke, A. T., Maggs, J. E., and Morales, G. J. Mon . "Experimental study of fluctuations excited by a narrow temperature filament in a magnetized plasma". United States. doi:10.1063/1.873957.
@article{osti_20216029,
title = {Experimental study of fluctuations excited by a narrow temperature filament in a magnetized plasma},
author = {Burke, A. T. and Maggs, J. E. and Morales, G. J.},
abstractNote = {A systematic study is made of the spontaneous growth of fluctuations in temperature, density, and magnetic field in a narrow (on the order of the electron skin depth) field-aligned temperature filament embedded in a large magnetized plasma. Two broad classes of fluctuation (''low'' and ''high'' frequency modes) have been identified and studied in detail. A high-frequency drift-Alfven mode grows at frequencies about one tenth the ion gyrofrequency in the region of the filament where the temperature gradient is large. The measured radial profiles of the density and magnetic field fluctuations associated with this mode agree well with theoretical predictions. The high-frequency mode has been observed to exhibit several interesting nonlinear features, including steepening wave form, progression in azimuthal mode number, coupling to the low frequency mode with subsequent sideband generation, and eventually a transition to broad band turbulence. The nature of the low-frequency mode which has frequencies about one fiftieth of the ion gyrofrequency is less certain, but it has been identified as a spatially localized, azimuthally symmetric mode consisting primarily of temperature fluctuations. Both the high and low-frequency modes give rise to electron heat transport at rates in excess of the classical values. (c) 2000 American Institute of Physics.},
doi = {10.1063/1.873957},
journal = {Physics of Plasmas},
issn = {1070-664X},
number = 5,
volume = 7,
place = {United States},
year = {2000},
month = {5}
}