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Title: Current profile redistribution driven by neutral beam injection in a reversed-field pinch

Abstract

Neutral beam injection in reversed-field pinch (RFP) plasmas on the Madison Symmetric Torus [Dexter et al., Fusion Sci. Technol. 19, 131 (1991)] drives current redistribution with increased on-axis current density but negligible net current drive. Internal fluctuations correlated with tearing modes are observed on multiple diagnostics; the behavior of tearing mode correlated structures is consistent with flattening of the safety factor profile. The first application of a parametrized model for island flattening to temperature fluctuations in an RFP allows inferrence of rational surface locations for multiple tearing modes. The m = 1, n = 6 mode is observed to shift inward by 1.1 ± 0.6 cm with neutral beam injection. Tearing mode rational surface measurements provide a strong constraint for equilibrium reconstruction, with an estimated reduction of q{sub 0} by 5% and an increase in on-axis current density of 8% ± 5%. The inferred on-axis current drive is consistent with estimates of fast ion density using TRANSP [Goldston et al., J. Comput. Phys. 43, 61 (1981)].

Authors:
 [1]; ;  [2]; ; ;  [1];  [2]
  1. Department of Physics and Astronomy, University of California Los Angeles 475 Portola Plaza, Los Angeles, California 90095 (United States)
  2. Department of Physics, University of Wisconsin-Madison 1150 University Ave., Madison, Wisconsin 53706 (United States)
Publication Date:
OSTI Identifier:
22600239
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 23; Journal Issue: 5; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1070-664X
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; BEAM INJECTION; CURRENT DENSITY; EQUILIBRIUM; FLUCTUATIONS; ION DENSITY; IONS; ISLANDS; LIMITING VALUES; MODE RATIONAL SURFACES; PLASMA; REVERSED-FIELD PINCH DEVICES; REVERSE-FIELD PINCH; TEARING INSTABILITY

Citation Formats

Parke, E., Department of Physics, University of Wisconsin-Madison 1150 University Ave., Madison, Wisconsin 53706, Anderson, J. K., Den Hartog, D. J., Brower, D. L., Ding, W. X., Lin, L., Johnson, C. A., and Department of Physics, Auburn University 206 Allison Laboratory, Auburn, Alabama 36849. Current profile redistribution driven by neutral beam injection in a reversed-field pinch. United States: N. p., 2016. Web. doi:10.1063/1.4946019.
Parke, E., Department of Physics, University of Wisconsin-Madison 1150 University Ave., Madison, Wisconsin 53706, Anderson, J. K., Den Hartog, D. J., Brower, D. L., Ding, W. X., Lin, L., Johnson, C. A., & Department of Physics, Auburn University 206 Allison Laboratory, Auburn, Alabama 36849. Current profile redistribution driven by neutral beam injection in a reversed-field pinch. United States. https://doi.org/10.1063/1.4946019
Parke, E., Department of Physics, University of Wisconsin-Madison 1150 University Ave., Madison, Wisconsin 53706, Anderson, J. K., Den Hartog, D. J., Brower, D. L., Ding, W. X., Lin, L., Johnson, C. A., and Department of Physics, Auburn University 206 Allison Laboratory, Auburn, Alabama 36849. 2016. "Current profile redistribution driven by neutral beam injection in a reversed-field pinch". United States. https://doi.org/10.1063/1.4946019.
@article{osti_22600239,
title = {Current profile redistribution driven by neutral beam injection in a reversed-field pinch},
author = {Parke, E. and Department of Physics, University of Wisconsin-Madison 1150 University Ave., Madison, Wisconsin 53706 and Anderson, J. K. and Den Hartog, D. J. and Brower, D. L. and Ding, W. X. and Lin, L. and Johnson, C. A. and Department of Physics, Auburn University 206 Allison Laboratory, Auburn, Alabama 36849},
abstractNote = {Neutral beam injection in reversed-field pinch (RFP) plasmas on the Madison Symmetric Torus [Dexter et al., Fusion Sci. Technol. 19, 131 (1991)] drives current redistribution with increased on-axis current density but negligible net current drive. Internal fluctuations correlated with tearing modes are observed on multiple diagnostics; the behavior of tearing mode correlated structures is consistent with flattening of the safety factor profile. The first application of a parametrized model for island flattening to temperature fluctuations in an RFP allows inferrence of rational surface locations for multiple tearing modes. The m = 1, n = 6 mode is observed to shift inward by 1.1 ± 0.6 cm with neutral beam injection. Tearing mode rational surface measurements provide a strong constraint for equilibrium reconstruction, with an estimated reduction of q{sub 0} by 5% and an increase in on-axis current density of 8% ± 5%. The inferred on-axis current drive is consistent with estimates of fast ion density using TRANSP [Goldston et al., J. Comput. Phys. 43, 61 (1981)].},
doi = {10.1063/1.4946019},
url = {https://www.osti.gov/biblio/22600239}, journal = {Physics of Plasmas},
issn = {1070-664X},
number = 5,
volume = 23,
place = {United States},
year = {Sun May 15 00:00:00 EDT 2016},
month = {Sun May 15 00:00:00 EDT 2016}
}