Prospects of a stationary tokamak reactor

Based on recent progress in world tokamak research, the prospects of continuous operation of a tokamak fusion power reactor are discussed. Efficient steady state operation (Q>30) becomes feasible when a large fraction of the plasma current (>70%) is driven by the bootstrap current. Moderate current (I_p approximately 10-20 MA) and an enhanced confinement mode of operation are the key for efficient steady state operation. High magnetic fields (B_t=8-11T) and high Troyon factors ( beta _N>3.5) are required to attain high beta _p operation and a reasonably high fusion power density. Control of the current and edge pressure profiles is necessary for high beta _N operation with a high bootstrap fraction. It is proposed that the Next Step Tokamak should be optimized for continuous operation as well as high current pulsed operation.