Abstract Details

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icc06poster_sovinec.pdf2006-03-08 08:58:42Carl Sovinec

Numerical studies of line-tied kink modes

Author: Carl Sovinec
Submitted: 2005-12-21 23:19:14

Co-authors: C. S. Carey, C. B. Forest, R. J. Fonck, and T. K. Fowler

Contact Info:
University of Wisconsin-Madison
1500 Engineering Drive
Madison, WI   53706-1
USA

Abstract Text:
The MHD kink instability in plasma pinches with bias magnetic field is receiving renewed interest. It provides a vehicle for investigating line-tied magnetic reconnection, and it has a central role in the magnetic relaxation of electrostatic current drive in spheromaks and spherical tori. Here we describe numerical results from the NIMROD code on an assortment of line-tied kink configurations. Relaxation limitations are investigated with basic resistive MHD computation, and we compare results with a minimum-dissipation relaxation model that predicts nonuniform parallel current in strongly driven conditions. Simulations of the kink mode in the Rotating Wall Machine combine nonlinear three-dimensional MHD with collisional transport, whereby temperature-dependent transport coefficients realistically govern the current-channel width according to the size of a heat source located at the upstream electrode. We compare with experimental results that show deflection of the current channel upon saturation of the kink instability. Finally, we consider the self-merger and relaxation of a helical current channel that models electrostatic injection via plasma guns for noninductive startup in the Pegasus Spherical Torus.

Characterization: E6

Comments:

The University of Texas at Austin

Innovative Confinement Concepts Workshop
February 13-16, 2006
Austin, Texas

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