Stabilization of external kink modes in tokamak
Calculations show that the rotation of a tokamak plasma, coupled with a resistive wall, can stabilise the pressure-driven external kink mode and significantly raise the beta limit imposed by these modes. These results are obtained with two MHD stability codes (NOVA-X, a modification of the NOVA-W code, and MARS) which include a resistive wall in the vacuum calculation. The effect of rotation velocity and wall position on the stabilisation of external kinks for various equilibria is given. Two types of modes occur: those which are nearly locked to the wall and those which rotate with the plasma. For the wall-locked modes the stabilising effect of rotation increases with increasing wall distance. This leads to a window of stability between the threshold wall distance for a given rotation speed and the marginal wall position for the ideal mode. The coupling of the sound waves is found to increase considerably the magnitude of the stabilisation.
Bibliographic Reference: Article: Bulletin of the American Physical Society, Vol. 38 (1993) No. 10, p. 2013
Record Number: 199311630 / Last updated on: 1994-11-28
Original language: en
Available languages: en