Physics of steady-state operation of tokamaks

Kikuchi, Mitsuru

The steady state operation has been one of important research subjects in tokamak for more than 20 years. The major feature of efficient steady state operation of tokamak is the maximum utilization of the bootstrap current. Since bootstrap current fraction is proportional to poloidal beta, the reactor should operate in high toroidal beta regime. Scenarios needs wall stabilization with finite resistivity of the wall. The physics of toroidal rotation attracts more attention since even small toroidal rotation is important for stabilization of RWM. In this paper, structure of 1st order flow on the flux surface is revisited and the role of thermal flow qdT/dr on toroidal rotation is surveyed with respect to difference between bulk ion and impurity, and offset toroidal rotation due to non-axisymmetric field.