Effects of a resistive wall on MHD instabilities
Linear and non-linear MHD calculations are presented which examine the effect of a finite conductivity, resistive wall on plasma stability. Near q = 2 in the tokamak and generally in the RFP, ideal modes are found, with a growth rate which varies inversely with the wall time constant. Resistive tearing modes can also be destabilised by a finite conductivity wall, but sufficiently fast plasma rotation can in turn stabilise these instabilities. Non-linearly it is shown that the eddy currents driven in the resistive wall, by rotating MHD activity, produce a torque which opposes and slows the plasma rotation. This effect can be particularly strong in the RFP and leads to mode lock times which are shorter than in the tokamak.
Bibliographic Reference: Report: CLM-P853 EN (1989)
Availability: Available from the Librarian, UKAEA, Culham Laboratory, Abingdon, Oxon. OX14 3DB (GB)
Record Number: 199010094 / Last updated on: 1994-12-01
Original language: en
Available languages: en