skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Plasma rotation driven by static nonresonant magnetic fields

Abstract

Recent experiments in high temperature DIII-D tokamak [J. L. Luxon, Nucl. Fusion 42, 64 (2002)] plasmas reported the first observation of plasma acceleration driven by the application of static nonresonant magnetic fields (NRMFs), with resulting improvement in the global energy confinement time. Although the braking effect of static magnetic field asymmetries is well known, recent theory [A. J. Cole et al., Phys. Rev. Lett. 99, 065001 (2007)] predicts that in some circumstances they lead instead to an increase in rotation frequency toward a 'neoclassical offset' rate in a direction opposed to the plasma current. We report the first experimental confirmation of this surprising result. The measured NRMF torque shows a strong dependence on both plasma density and temperature, above expectations from neoclassical theory. The consistency between theory and experiment improves with modifications to the expression of the NRMF torque accounting for a significant role of the plasma response to the external field and for the beta dependence of the plasma response, although some discrepancy remains. The magnitude and direction of the observed offset rotation associated with the NRMF torque are consistent with neoclassical theory predictions. The offset rotation rate is about 1% of the Alfven frequency or more than doublemore » the rotation needed for stable operation at high {beta}{sub N} above the n=1 no-wall kink limit in DIII-D.« less

Authors:
; ; ; ; ; ;  [1]; ;  [2]; ;  [3]
  1. General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States)
  2. Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543-0451 (United States)
  3. Columbia University, 2960 Broadway, New York, New York 10027-1754 (United States)
Publication Date:
OSTI Identifier:
21277170
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 16; Journal Issue: 5; Other Information: DOI: 10.1063/1.3129164; (c) 2009 American Institute of Physics; 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; CONFINEMENT TIME; DOUBLET-3 DEVICE; ELECTRON TEMPERATURE; ION TEMPERATURE; MAGNETIC FIELDS; NEOCLASSICAL TRANSPORT THEORY; PLASMA ACCELERATION; PLASMA DENSITY; ROTATION

Citation Formats

Garofalo, A M, Burrell, K H, DeBoo, J C, DeGrassie, J S, Jackson, G L, Schaffer, M J, Strait, E J, Solomon, W M, Park, J -K, Lanctot, M, and Reimerdes, H. Plasma rotation driven by static nonresonant magnetic fields. United States: N. p., 2009. Web. doi:10.1063/1.3129164.
Garofalo, A M, Burrell, K H, DeBoo, J C, DeGrassie, J S, Jackson, G L, Schaffer, M J, Strait, E J, Solomon, W M, Park, J -K, Lanctot, M, & Reimerdes, H. Plasma rotation driven by static nonresonant magnetic fields. United States. https://doi.org/10.1063/1.3129164
Garofalo, A M, Burrell, K H, DeBoo, J C, DeGrassie, J S, Jackson, G L, Schaffer, M J, Strait, E J, Solomon, W M, Park, J -K, Lanctot, M, and Reimerdes, H. 2009. "Plasma rotation driven by static nonresonant magnetic fields". United States. https://doi.org/10.1063/1.3129164.
@article{osti_21277170,
title = {Plasma rotation driven by static nonresonant magnetic fields},
author = {Garofalo, A M and Burrell, K H and DeBoo, J C and DeGrassie, J S and Jackson, G L and Schaffer, M J and Strait, E J and Solomon, W M and Park, J -K and Lanctot, M and Reimerdes, H},
abstractNote = {Recent experiments in high temperature DIII-D tokamak [J. L. Luxon, Nucl. Fusion 42, 64 (2002)] plasmas reported the first observation of plasma acceleration driven by the application of static nonresonant magnetic fields (NRMFs), with resulting improvement in the global energy confinement time. Although the braking effect of static magnetic field asymmetries is well known, recent theory [A. J. Cole et al., Phys. Rev. Lett. 99, 065001 (2007)] predicts that in some circumstances they lead instead to an increase in rotation frequency toward a 'neoclassical offset' rate in a direction opposed to the plasma current. We report the first experimental confirmation of this surprising result. The measured NRMF torque shows a strong dependence on both plasma density and temperature, above expectations from neoclassical theory. The consistency between theory and experiment improves with modifications to the expression of the NRMF torque accounting for a significant role of the plasma response to the external field and for the beta dependence of the plasma response, although some discrepancy remains. The magnitude and direction of the observed offset rotation associated with the NRMF torque are consistent with neoclassical theory predictions. The offset rotation rate is about 1% of the Alfven frequency or more than double the rotation needed for stable operation at high {beta}{sub N} above the n=1 no-wall kink limit in DIII-D.},
doi = {10.1063/1.3129164},
url = {https://www.osti.gov/biblio/21277170}, journal = {Physics of Plasmas},
issn = {1070-664X},
number = 5,
volume = 16,
place = {United States},
year = {Fri May 15 00:00:00 EDT 2009},
month = {Fri May 15 00:00:00 EDT 2009}
}