High field tokamak reactor with force balanced coils as a volumetric neutron source

摘要

A DT sub-ignited tokamak reactor has been investigated that has an average neutron wall loading of 1 MW/m~2 and is based on a novel coil concept to generate a strong magnetic field. When the aspect ratio of the coil winding is about 1.7, the forces in the major direction are balanced with the winding pitch of two poloidal rotations round the torus. Thus force balanced coils can be designed which consist of twisted loops in a shape like a figure of cight. Although the coil current has a toroidal components, the poloidal component of the produced magnetic field is made to be negligible inside the winding by modulating the winding pitch. The net centring force is reduced by a factor of 10 from that exerted on toroidal magnetic coils of the same dimension. The authors designed a steady state tokamak reactor with force balanced coils. The fusion reaction of Q_DT approx 3.7 is maintained with 58 MW of neutral beam power into a plasma with a major radius of 3.64 m, a minor radius of 0.80 m, an elongation of 1.7, a plasma current of 6.0 MA, an H factor of 2 and a toroidal field on the axis of 8.4 T.