High field tokamak reactors

Abstract

The use of high magnetic fields (magnetic field at the plasma axis B t = 7–14 T) in ignited tokamak reactor designs is described. High field operation provides a means of significantly reducing reactor size, of increasing fusion power density and of facilitating reactor maintenance by allowing for a reduction in the complexity of the overall system. A design has been developed for an ignition test reactor which uses copper magnets with a Bitter plate design. The toroidal magnetic field at the plasma axis is 12.5 T. The ignition test reactor design utilizes neutral beam heating in conjunction with adiabatic compression of the plasma in major radius. A design for a demonstration power reactor is described. A Nb 3Sn toroidal field magnet with a field of 13.1 T at the coil winding and 7.4 T at the plasma is utilized. Future directions for high field reactor studies include considerations of RF heated ignition test reactors and the use of 200 GHz gyrotron radiation for electron cyclotron resonance heating of demonstration power reactor plasmas.