Resistive Modes in CDXU
Abstract
CDXU is an attractive device to model to benchmark resistive MHD codes. Its small size and low temperature (S < 10^5) make it possible to simulate MHD events using actual experimental parameters in a reasonable time on presentday computers. The dominant MHD activity during normal operation is the sawtooth oscillation, a resistive internal kink mode with toroidal mode number n=1 and dominant poloidal mode number m=1 [1]. We model both the linear growth of the instability and the nonlinear reconnection event at the q=1 rational surface (the sawtooth crash) using the M3D code [2]. Under the assumption of constant resistivity the crash can either lead to a disruption or to a quiescent state with q on axis above 1, depending on the initial value of q_0. With Spitzer resistivity, which depends on the temperature and exhibits strong gradients, the plasma can also be unstable to a rippling mode [3], centered at the q=2 surface, whose strength depends on the value of the parallel thermal conductivity and on the profile shapes and aspect ratio. [1] D. Stutman, et al., Plasma Phys. Control. Fusion 41, 867 (1999). [2] W. Park et al., Phys. Plasmas 6, 1796 (1999). [3] H.P. Furth, J. Killeen, and M.N. Rosenbluth, Phys. Fluids 6, 459 (1963).
 Publication:

APS Division of Plasma Physics Meeting Abstracts
 Pub Date:
 October 2003
 Bibcode:
 2003APS..DPPQP1123B