A new technique to optimize the coil winding path for the arbitrarily distributed magnetic field and application to a helical confinement system

A new technique to calculate the optimum modular coil winding path for a helical plasma confinement system has been developed. The technique is based on current potential on an arbitrary surface with finite elements and singular value decomposition (SVD). No function is assumed for the current potential distribution, and then, little error occurs from modeling. The SVD is applied to the response matrix from the current potential to the magnetic field on the plasma surface. The current distribution is constructed from an eigen distribution obtained through SVD so that the normal field component is small. The coil winding path is determined along the flow lines or equi-contour lines of current potential. The current on the obtained coil winding path was confirmed able to generate good magnetic surfaces.