Consideration of the Magnetic Field Ripple in the Design of Plasma Edge Components for Tore Supra

Design of edge components for a plasma device requires a description of heat and particle flows at the edge of the device. In a tokamak, the ripple of the toroidal field affects the direction of such flows by affecting the direction of the field. In Tore Supra, in particular, the ripple is large (≤8% at the outboard edge). This causes a substantial (factor of ≤2) increase in heat flux deposited onto the limiter and antenna face. It also reduces the particle removal efficiency of the pump limiters by increasing the distance between the throat opening and the plasma edge. It is therefore important to include the ripple when designing plasma edge components such as pump limiters and radio-frequency antennas. A simple, but accurate, scheme for field line tracing is found and used to study this effect. Modeling of the ripple is discussed.