Density scaling of the threshold for locked mode instability in presence of toroidal field ripples in a tokamak
The nonlinear excitation of magnetic islands in a tokamak by external resonant magnetic perturbation is examined. The perturbation amplitude threshold for the appearance of a locked mode is determined for a tokamak with a rippled toroidal field. It is shown that the critical value of the magnetic field tends to be increased by the ripple induced damping of toroidal rotation. Qualitative aspects of the experimentally observed reduced scaling of the threshold density for mode locking, can be predicted in the regime of low viscosity and dominant plasma inertial effects.
Bibliographic Reference: Report: JET-P(96)54 EN (1996) 15pp.
Availability: Available from the Publications Officer, JET Joint Undertaking, Abingdon, Oxon, OX14 3EA (GB)
Record Number: 199710052 / Last updated on: 1997-02-26
Original language: en
Available languages: en