Ferromagnetic and Resistive Wall Effects on Beta Limit in a Tokamak
G. Kurita, T. Tuda, S. Ishida, S. Takeji, A. Sakasai, M. Matsukawa, T. Ozeki, M. Kikuchi, M. Azumi
Naka Fusion Research Establishment, Japan Atomic Energy Research Institute, Mukoyama, Naka-machi, Naka-gun, Ibaraki-ken, Japan 311-0193
Abstract.
Ferromagnetic and resistive wall effect on beta limit in a tokamak is investigated. It is shown that the beta limit is reduced to 90% of that without ferromagnetic effect for high aspect ratio tokamak, if the ferromagnetic wall of relative permeability of 2 is used. The effect of toroidal plasma flow is also investigated, and the flow velocity of 0.03vta, vta is toroidal Alfven velocity, is sufficient for the resistive wall to have stability effect of ideal wall. Both the resistive wall and ideal kink modes are destabilized by the ferromagnetic wall effects.