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Title: Beta-limiting MHD Instabilities in Improved-performance NSTX Spherical Torus Plasmas

Abstract

Global magnetohydrodynamic stability limits in the National Spherical Torus Experiment (NSTX) have increased significantly recently due to a combination of device and operational improvements. First, more routine H-mode operation with broadened pressure profiles allows access to higher normalized beta and lower internal inductance. Second, the correction of a poloidal field coil induced error-field has largely eliminated locked tearing modes during normal operation and increased the maximum achievable beta. As a result of these improvements, peak beta values have reached (not simultaneously) {beta}{sub t} = 35%, {beta}{sub N} = 6.4, <{beta}{sub N}> = 4.5, {beta}{sub N}/l{sub i} = 10, and {beta}{sub P} = 1.4. High {beta}{sub P} operation with reduced tearing activity has allowed a doubling of discharge pulse-length to just over 1 second with sustained periods of {beta}{sub N} {approx} 6 above the ideal no-wall limit and near the with-wall limit. Details of the {beta} limit scalings and {beta}-limiting instabilities in various operating regimes are described.

Authors:
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Publication Date:
Research Org.:
Princeton Plasma Physics Lab., NJ (US)
Sponsoring Org.:
USDOE Office of Science (SC) (US)
OSTI Identifier:
814017
Report Number(s):
PPPL-3815
TRN: US0303973
DOE Contract Number:  
AC02-76CH03073
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 29 May 2003
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; INDUCTANCE; MAGNETOHYDRODYNAMICS; STABILITY; HIGH-BETA PLASMA; HIGH-BETA PLASMAS; MHD INSTABILITY; TOKAMAKS, NSTX

Citation Formats

J.E. Menard, M.G. Bell, R.E. Bell, E.D. Fredrickson D.A. Gates: S.M. Kaye, B.P. LeBlanc, R. Maingi, D. Mueller, S.A. Sabbagh, D. Stutman, C.E. Bush, D.W. Johnson, R. Kaita, H.W. Kugel, R.J. Maqueda, F. Paoletti, S.F Paul, M. Ono, Y.-K.M. Peng, C.H. Skinner, E.J. Synakowski, and the NSTX Research Team. Beta-limiting MHD Instabilities in Improved-performance NSTX Spherical Torus Plasmas. United States: N. p., 2003. Web. doi:10.2172/814017.
J.E. Menard, M.G. Bell, R.E. Bell, E.D. Fredrickson D.A. Gates: S.M. Kaye, B.P. LeBlanc, R. Maingi, D. Mueller, S.A. Sabbagh, D. Stutman, C.E. Bush, D.W. Johnson, R. Kaita, H.W. Kugel, R.J. Maqueda, F. Paoletti, S.F Paul, M. Ono, Y.-K.M. Peng, C.H. Skinner, E.J. Synakowski, & the NSTX Research Team. Beta-limiting MHD Instabilities in Improved-performance NSTX Spherical Torus Plasmas. United States. doi:10.2172/814017.
J.E. Menard, M.G. Bell, R.E. Bell, E.D. Fredrickson D.A. Gates: S.M. Kaye, B.P. LeBlanc, R. Maingi, D. Mueller, S.A. Sabbagh, D. Stutman, C.E. Bush, D.W. Johnson, R. Kaita, H.W. Kugel, R.J. Maqueda, F. Paoletti, S.F Paul, M. Ono, Y.-K.M. Peng, C.H. Skinner, E.J. Synakowski, and the NSTX Research Team. Thu . "Beta-limiting MHD Instabilities in Improved-performance NSTX Spherical Torus Plasmas". United States. doi:10.2172/814017. https://www.osti.gov/servlets/purl/814017.
@article{osti_814017,
title = {Beta-limiting MHD Instabilities in Improved-performance NSTX Spherical Torus Plasmas},
author = {J.E. Menard and M.G. Bell and R.E. Bell and E.D. Fredrickson D.A. Gates: S.M. Kaye and B.P. LeBlanc and R. Maingi and D. Mueller and S.A. Sabbagh and D. Stutman and C.E. Bush and D.W. Johnson and R. Kaita and H.W. Kugel and R.J. Maqueda and F. Paoletti and S.F Paul and M. Ono and Y.-K.M. Peng and C.H. Skinner and E.J. Synakowski and the NSTX Research Team},
abstractNote = {Global magnetohydrodynamic stability limits in the National Spherical Torus Experiment (NSTX) have increased significantly recently due to a combination of device and operational improvements. First, more routine H-mode operation with broadened pressure profiles allows access to higher normalized beta and lower internal inductance. Second, the correction of a poloidal field coil induced error-field has largely eliminated locked tearing modes during normal operation and increased the maximum achievable beta. As a result of these improvements, peak beta values have reached (not simultaneously) {beta}{sub t} = 35%, {beta}{sub N} = 6.4, <{beta}{sub N}> = 4.5, {beta}{sub N}/l{sub i} = 10, and {beta}{sub P} = 1.4. High {beta}{sub P} operation with reduced tearing activity has allowed a doubling of discharge pulse-length to just over 1 second with sustained periods of {beta}{sub N} {approx} 6 above the ideal no-wall limit and near the with-wall limit. Details of the {beta} limit scalings and {beta}-limiting instabilities in various operating regimes are described.},
doi = {10.2172/814017},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu May 29 00:00:00 EDT 2003},
month = {Thu May 29 00:00:00 EDT 2003}
}

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