Numerical study of magnetic field configuration for FFHR from a viewpoint of divertor and edge field structure

A new divertor configuration called helical X point divertor (HXD) for a heliotron type fusion reactor FFHR is proposed, which has relatively wide target plates near two X points helically rotating along the torus. It has a clear divertor magnetic configuration with enough space to install blanket modules all around the torus. From the numerical calculation, it has been found that the wetted area on target plates for the divertor flux is sufficiently large to receive its high heat load. In this new divertor configuration, there exists another attractive feature to enhance the divertor function, with existence of intrinsic magnetic islands in the edge ergodic region.