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Shaping effects on toroidal magnetohydrodynamic modes in the presence of plasma and wall resistivity

Authors :
Dylan Brennan
Dov Rhodes
Richard Fitzpatrick
Andrew J. Cole
Michael E. Mauel
John M. Finn
M. Li
G.A. Navratil
Source :
Physics of Plasmas. 25:012517
Publication Year :
2018
Publisher :
AIP Publishing, 2018.

Abstract

This study explores the effects of plasma shaping on magnetohydrodynamic mode stability and rotational stabilization in a tokamak, including both plasma and wall resistivity. Depending upon the plasma shape, safety factor, and distance from the wall, the β-limit for rotational stabilization is given by either the resistive-plasma ideal-wall (tearing mode) limit or the ideal-plasma resistive-wall (resistive wall mode) limit. In order to explore this broad parameter space, a sharp-boundary model is developed with a realistic geometry, resonant tearing surfaces, and a resistive wall. The β-limit achievable in the presence of stabilization by rigid plasma rotation, or by an equivalent feedback control with imaginary normal-field gain, is shown to peak at specific values of elongation and triangularity. It is shown that the optimal shaping with rotation typically coincides with transitions between tearing-dominated and wall-dominated mode behavior.

Details

ISSN :
10897674 and 1070664X
Volume :
25
Database :
OpenAIRE
Journal :
Physics of Plasmas
Accession number :
edsair.doi...........9ee2f3b92ad8638c35d8485dcea182a6
Full Text :
https://doi.org/10.1063/1.4991873