Analyses of a scheme to improve the SOL transport properties by plasma current modulation
Ergodisation of the plasma boundary by helical perturbation fields has been proposed and investigated experimentally as a means of improving the desired properties of the SOL for heat and particle exhaust. It was shown that, depending on the stochasticity parameter, a chain of overlapping islands gives rise to a region with almost vanishing particle and energy confinement. This paper investigates how to excite tearing mode islands periodically by a modulation of the plasma current with a rise and a subsequent decay phase. The first phase is intended to generate radially hollow current density profiles and, thus, nonmonotonic q-profiles, revealing maxima in the vicinity of the plasma boundary. The second phase is needed to retrieve the original q-profile just before the respective current rise phase. The evolution of the q-profile is tracked by the 1d-transport code TORUS I, and its stability with respect to tearing modes is analysed by the RSF-code.
Bibliographic Reference: Article: 18th European Conference on Controlled Fusion and Plasma Physics, Vol. III (1991) pp. 9-12
Record Number: 199111399 / Last updated on: 1994-12-02
Original language: en
Available languages: en