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

Title: Microinstability analysis of DIII-D high-performance discharges

Abstract

The kinetic stability properties in a number of high performance discharges from the DIII-D tokamak [R. D. Stambaugh for the DIII-D Team, {ital Plasma} {ital Physics} {ital and} {ital Controlled} {ital Nuclear} {ital Fusion} {ital Research}, 1994 (International Atomic Energy Agency, Vienna, 1995), Vol. 1, p. 83] have been analyzed utilizing a comprehensive kinetic eigenvalue code. The instability considered is the toroidal drift mode [trapped-electron-ion temperature gradient ({eta}{sub {ital i}}) mode]. This code has been interfaced with equilibria specific to DIII-D plasmas. Experimentally measured kinetic profile data, along with motional stark effect data and external magnetic data, was used, and the corresponding magnetohydrodynamic (MHD) equilibria were computed numerically. In particular, a low confinement mode (L-mode) case, a high-{ital l}{sub {ital i}} high confinement mode (H-mode) case, a very high confinement mode (VH-mode) case, and a high plasma pressure/poloidal magnetic pressure ({beta}{sub {ital p}}) case have been analyzed. For the L-mode case, a wide region of instability was found, while for the H-mode and VH-mode and high-{beta}{sub {ital p}} cases, only relatively narrow regions of instability were found. An assessment of the influence of velocity-shear flow on these instabilities has also been made, as well as of changes in the electronmore » and ion temperature gradients and density gradients. While the experimental values of the sheared toroidal flow velocity are not sufficient to stabilize the instability, an increase by a factor of two to four in the flow velocity could completely stabilize this mode. {copyright} {ital 1996 American Institute of Physics.}« less

Authors:
 [1];  [2];  [1]
  1. Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543-0451 (United States)
  2. General Atomics, San Diego, California 92186-9784 (United States)
Publication Date:
Research Org.:
Princeton Plasma Physics Laboratory
OSTI Identifier:
392060
DOE Contract Number:  
AC02-76CH03073; AC03-89ER51114
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 3; Journal Issue: 11; Other Information: PBD: Nov 1996
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION; DOUBLET-3 DEVICE; DRIFT INSTABILITY; MHD EQUILIBRIUM; H-MODE PLASMA CONFINEMENT; HIGH-BETA PLASMA; PLASMA MICROINSTABILITIES; COMPUTER CODES; PLASMA SIMULATION

Citation Formats

Rewoldt, G, Lao, L L, and Tang, W M. Microinstability analysis of DIII-D high-performance discharges. United States: N. p., 1996. Web. doi:10.1063/1.871539.
Rewoldt, G, Lao, L L, & Tang, W M. Microinstability analysis of DIII-D high-performance discharges. United States. doi:10.1063/1.871539.
Rewoldt, G, Lao, L L, and Tang, W M. Fri . "Microinstability analysis of DIII-D high-performance discharges". United States. doi:10.1063/1.871539.
@article{osti_392060,
title = {Microinstability analysis of DIII-D high-performance discharges},
author = {Rewoldt, G and Lao, L L and Tang, W M},
abstractNote = {The kinetic stability properties in a number of high performance discharges from the DIII-D tokamak [R. D. Stambaugh for the DIII-D Team, {ital Plasma} {ital Physics} {ital and} {ital Controlled} {ital Nuclear} {ital Fusion} {ital Research}, 1994 (International Atomic Energy Agency, Vienna, 1995), Vol. 1, p. 83] have been analyzed utilizing a comprehensive kinetic eigenvalue code. The instability considered is the toroidal drift mode [trapped-electron-ion temperature gradient ({eta}{sub {ital i}}) mode]. This code has been interfaced with equilibria specific to DIII-D plasmas. Experimentally measured kinetic profile data, along with motional stark effect data and external magnetic data, was used, and the corresponding magnetohydrodynamic (MHD) equilibria were computed numerically. In particular, a low confinement mode (L-mode) case, a high-{ital l}{sub {ital i}} high confinement mode (H-mode) case, a very high confinement mode (VH-mode) case, and a high plasma pressure/poloidal magnetic pressure ({beta}{sub {ital p}}) case have been analyzed. For the L-mode case, a wide region of instability was found, while for the H-mode and VH-mode and high-{beta}{sub {ital p}} cases, only relatively narrow regions of instability were found. An assessment of the influence of velocity-shear flow on these instabilities has also been made, as well as of changes in the electron and ion temperature gradients and density gradients. While the experimental values of the sheared toroidal flow velocity are not sufficient to stabilize the instability, an increase by a factor of two to four in the flow velocity could completely stabilize this mode. {copyright} {ital 1996 American Institute of Physics.}},
doi = {10.1063/1.871539},
journal = {Physics of Plasmas},
number = 11,
volume = 3,
place = {United States},
year = {1996},
month = {11}
}