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Title: Observation of modes at frequencies near the second Alfven gap in TFTR

Abstract

Modes have been observed near the frequency of the second Alfven gap during off-axis H-minority heating experiments on TFTR. The observation of these modes is surprising in that the second gap, which is generally opened with ellipticity, is expected to be small, of order (r/R){sup 2}, since TFTR plasmas are circular in cross-section. A model is proposed in which the second gap is opened by the fast ion beta, which is shown to be able to introduce mode coupling, much as toroidal effects introduce mode coupling for Toroidal Alfven Eigenmodes (TAE). The modes are seen with and without accompanying TAE mode activity. (c) 1999 American Institute of Physics.

Authors:
 [1];  [2];  [1];  [1];  [1];  [1];  [1];  [1]
  1. Princeton Plasma Physics Laboratory, Princeton, New Jersey (United States)
  2. Institute for Fusion Studies, University of Texas at Austin, Austin, Texas (United States)
Publication Date:
OSTI Identifier:
20216684
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; ICR HEATING; ALFVEN WAVES; POWER RANGE 01-10 MW; SAWTOOTH OSCILLATIONS; PLASMA INSTABILITY; EXPERIMENTAL DATA

Citation Formats

Fredrickson, E., Van Dam, J. W., Budny, R. V., Darrow, D., Fu, G. Y., Hosea, J., Phillips, C. K., and Wilson, J. R. Observation of modes at frequencies near the second Alfven gap in TFTR. United States: N. p., 1999. Web. doi:10.1063/1.59719.
Fredrickson, E., Van Dam, J. W., Budny, R. V., Darrow, D., Fu, G. Y., Hosea, J., Phillips, C. K., & Wilson, J. R. Observation of modes at frequencies near the second Alfven gap in TFTR. United States. doi:10.1063/1.59719.
Fredrickson, E., Van Dam, J. W., Budny, R. V., Darrow, D., Fu, G. Y., Hosea, J., Phillips, C. K., and Wilson, J. R. Mon . "Observation of modes at frequencies near the second Alfven gap in TFTR". United States. doi:10.1063/1.59719.
@article{osti_20216684,
title = {Observation of modes at frequencies near the second Alfven gap in TFTR},
author = {Fredrickson, E. and Van Dam, J. W. and Budny, R. V. and Darrow, D. and Fu, G. Y. and Hosea, J. and Phillips, C. K. and Wilson, J. R.},
abstractNote = {Modes have been observed near the frequency of the second Alfven gap during off-axis H-minority heating experiments on TFTR. The observation of these modes is surprising in that the second gap, which is generally opened with ellipticity, is expected to be small, of order (r/R){sup 2}, since TFTR plasmas are circular in cross-section. A model is proposed in which the second gap is opened by the fast ion beta, which is shown to be able to introduce mode coupling, much as toroidal effects introduce mode coupling for Toroidal Alfven Eigenmodes (TAE). The modes are seen with and without accompanying TAE mode activity. (c) 1999 American Institute of Physics.},
doi = {10.1063/1.59719},
journal = {AIP Conference Proceedings},
issn = {0094-243X},
number = 1,
volume = 485,
place = {United States},
year = {1999},
month = {9}
}