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Title: Transport with reversed shear in the National Spherical Torus Experiment

Abstract

In the National Spherical Torus Experiment (NSTX) [M. Ono et al., Nucl. Fusion 40, 557 (2000)], plasmas with strongly reversed magnetic shear, s{identical_to}(r/q)(dq/dr)<0, in the plasma core exhibit a marked improvement in electron confinement compared to otherwise similar plasmas with positive or only weakly reversed magnetic shear. The q profile itself is determined by the early evolution of the plasma current, the plasma cross section, and the neutral-beam heating power. In the region of shear reversal, the electron thermal diffusivity can be significantly reduced. Detailed experimental investigation of this phenomenon has been made possible by the successful development of a motional Stark effect (MSE) polarimetry diagnostic suitable for the low magnetic field in NSTX, typically 0.35-0.55 T. Measurements of the electron and ion temperature, density, and plasma toroidal rotation profiles are also available with high spatial and temporal resolution for analysis of the plasma transport properties.

Authors:
;  [1]; ; ; ; ; ; ; ; ; ; ;  [2]; ; ; ;  [3];  [4];  [5];  [6]
  1. Nova Photonics, Inc., Princeton, New Jersey 08540 (United States)
  2. Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)
  3. Johns Hopkins University, Baltimore, Maryland 21218 (United States)
  4. Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830 (United States)
  5. University of Washington, Seattle, Washington 98195 (United States)
  6. Columbia University, New York, New York 10027 (United States)
Publication Date:
OSTI Identifier:
20975057
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 14; Journal Issue: 5; Other Information: DOI: 10.1063/1.2734124; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ELECTRIC CURRENTS; ELECTRON TEMPERATURE; ELECTRONS; HEATING; ION TEMPERATURE; MAGNETIC FIELD CONFIGURATIONS; MAGNETIC FIELDS; NSTX DEVICE; PLASMA; PLASMA BEAM INJECTION; PLASMA CONFINEMENT; PLASMA DENSITY; PLASMA DIAGNOSTICS; POLARIMETRY; REVERSED SHEAR; ROTATION; SPHERICAL CONFIGURATION; STARK EFFECT; THERMAL DIFFUSIVITY

Citation Formats

Levinton, F. M., Yuh, H., Bell, M. G., Bell, R. E., Fredrickson, E. D., Gates, D. A., Kaye, S. M., LeBlanc, B. P., Menard, J. E., Mikkelsen, D., Mueller, D., Rewoldt, G., Wang, W., Delgado-Aparicio, L., Finkenthal, M., Stutman, D., Tritz, K., Maingi, R., Raman, R., and Sabbagh, S. A.. Transport with reversed shear in the National Spherical Torus Experiment. United States: N. p., 2007. Web. doi:10.1063/1.2734124.
Levinton, F. M., Yuh, H., Bell, M. G., Bell, R. E., Fredrickson, E. D., Gates, D. A., Kaye, S. M., LeBlanc, B. P., Menard, J. E., Mikkelsen, D., Mueller, D., Rewoldt, G., Wang, W., Delgado-Aparicio, L., Finkenthal, M., Stutman, D., Tritz, K., Maingi, R., Raman, R., & Sabbagh, S. A.. Transport with reversed shear in the National Spherical Torus Experiment. United States. doi:10.1063/1.2734124.
Levinton, F. M., Yuh, H., Bell, M. G., Bell, R. E., Fredrickson, E. D., Gates, D. A., Kaye, S. M., LeBlanc, B. P., Menard, J. E., Mikkelsen, D., Mueller, D., Rewoldt, G., Wang, W., Delgado-Aparicio, L., Finkenthal, M., Stutman, D., Tritz, K., Maingi, R., Raman, R., and Sabbagh, S. A.. Tue . "Transport with reversed shear in the National Spherical Torus Experiment". United States. doi:10.1063/1.2734124.
@article{osti_20975057,
title = {Transport with reversed shear in the National Spherical Torus Experiment},
author = {Levinton, F. M. and Yuh, H. and Bell, M. G. and Bell, R. E. and Fredrickson, E. D. and Gates, D. A. and Kaye, S. M. and LeBlanc, B. P. and Menard, J. E. and Mikkelsen, D. and Mueller, D. and Rewoldt, G. and Wang, W. and Delgado-Aparicio, L. and Finkenthal, M. and Stutman, D. and Tritz, K. and Maingi, R. and Raman, R. and Sabbagh, S. A.},
abstractNote = {In the National Spherical Torus Experiment (NSTX) [M. Ono et al., Nucl. Fusion 40, 557 (2000)], plasmas with strongly reversed magnetic shear, s{identical_to}(r/q)(dq/dr)<0, in the plasma core exhibit a marked improvement in electron confinement compared to otherwise similar plasmas with positive or only weakly reversed magnetic shear. The q profile itself is determined by the early evolution of the plasma current, the plasma cross section, and the neutral-beam heating power. In the region of shear reversal, the electron thermal diffusivity can be significantly reduced. Detailed experimental investigation of this phenomenon has been made possible by the successful development of a motional Stark effect (MSE) polarimetry diagnostic suitable for the low magnetic field in NSTX, typically 0.35-0.55 T. Measurements of the electron and ion temperature, density, and plasma toroidal rotation profiles are also available with high spatial and temporal resolution for analysis of the plasma transport properties.},
doi = {10.1063/1.2734124},
journal = {Physics of Plasmas},
number = 5,
volume = 14,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}