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Title: Ion absorption effects in high-harmonic fast wave ray tracing theory

Abstract

Effects of finite ion temperature on the propagation and absorption characteristics of high-harmonic fast waves (HHFW) are investigated theoretically using a hot electron (cold ion) ray tracing code in combination with solutions of the full hot plasma dispersion relation. Ray tracing is performed on numerical solutions of the Grad-Shafranov equation and the hot plasma dispersion relation is solved along the resultant ray trajectory using the cold ion n{sub (parallel} {sub sign)}. As was observed previously (see Ref. [1]), for typical expected plasma parameters in the National Spherical Torus Experiment (NSTX) [2], ion absorption begins to appear between 0.5 and 1.0 keV local ion temperature at high deuterium cyclotron harmonics. Further, the ion power absorption rate is predicted to depend strongly on the launched parallel wavenumber [3,4]. Ray tracing on the full hot plasma dispersion relation has been attempted, but generally fails at high ion temperature near cyclotron harmonics primarily because the group velocity is ill-behaved. Such behavior usually suggests mode conversion to the ion-Bernstein wave (IBW). However, at sufficiently high n{sub (parallel} {sub sign)}, mode conversion becomes negligible and the total power flux (Poynting+kinetic) is positive definite, while ray tracing still fails. The underlying cause of this apparent paradox ismore » discussed. (c) 1999 American Institute of Physics.« less

Authors:
 [1];  [1];  [2]
  1. Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543-0451 (United States)
  2. University of California-San Diego (United States)
Publication Date:
OSTI Identifier:
20216704
Resource Type:
Journal Article
Journal Name:
AIP Conference Proceedings
Additional Journal Information:
Journal Volume: 485; Journal Issue: 1; Other Information: PBD: 20 Sep 1999; Journal ID: ISSN 0094-243X
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; HIGH-FREQUENCY HEATING; ION TEMPERATURE; BERNSTEIN MODE; ELECTRON TEMPERATURE; WKB APPROXIMATION; ION CYCLOTRON-RESONANCE; THEORETICAL DATA

Citation Formats

Menard, J. E., Phillips, C. K., and Mau, T. K. Ion absorption effects in high-harmonic fast wave ray tracing theory. United States: N. p., 1999. Web. doi:10.1063/1.59687.
Menard, J. E., Phillips, C. K., & Mau, T. K. Ion absorption effects in high-harmonic fast wave ray tracing theory. United States. doi:10.1063/1.59687.
Menard, J. E., Phillips, C. K., and Mau, T. K. Mon . "Ion absorption effects in high-harmonic fast wave ray tracing theory". United States. doi:10.1063/1.59687.
@article{osti_20216704,
title = {Ion absorption effects in high-harmonic fast wave ray tracing theory},
author = {Menard, J. E. and Phillips, C. K. and Mau, T. K.},
abstractNote = {Effects of finite ion temperature on the propagation and absorption characteristics of high-harmonic fast waves (HHFW) are investigated theoretically using a hot electron (cold ion) ray tracing code in combination with solutions of the full hot plasma dispersion relation. Ray tracing is performed on numerical solutions of the Grad-Shafranov equation and the hot plasma dispersion relation is solved along the resultant ray trajectory using the cold ion n{sub (parallel} {sub sign)}. As was observed previously (see Ref. [1]), for typical expected plasma parameters in the National Spherical Torus Experiment (NSTX) [2], ion absorption begins to appear between 0.5 and 1.0 keV local ion temperature at high deuterium cyclotron harmonics. Further, the ion power absorption rate is predicted to depend strongly on the launched parallel wavenumber [3,4]. Ray tracing on the full hot plasma dispersion relation has been attempted, but generally fails at high ion temperature near cyclotron harmonics primarily because the group velocity is ill-behaved. Such behavior usually suggests mode conversion to the ion-Bernstein wave (IBW). However, at sufficiently high n{sub (parallel} {sub sign)}, mode conversion becomes negligible and the total power flux (Poynting+kinetic) is positive definite, while ray tracing still fails. The underlying cause of this apparent paradox is discussed. (c) 1999 American Institute of Physics.},
doi = {10.1063/1.59687},
journal = {AIP Conference Proceedings},
issn = {0094-243X},
number = 1,
volume = 485,
place = {United States},
year = {1999},
month = {9}
}