Toroidal Field Coil System for Tokamaks with Improved Access to the Plasma Chamber

This invention involves two methods for reducing the toroidal magnetic field ripple. In the first method, toroidal field (TF) coils can be concentrated in a small number of columns on outboard side of the tokamak, which allow large regions of the outboard side to be removed for servicing the plasma chamber. The removable sections (“plugs”) are designed to modify the magnetic field so that the toroidal variation of the magnetic field (ripple) is acceptably low.  The second method uses a combination of ferritic steel placed mainly in the shadow of the TF outer legs and tiles of bulk superconductor placed inside the windowframe coils. This results in the mitigation of the TF ripple, allowing smaller numbers of TF coil outerlegs for the same net ripple at the plasma, hence greater access to the plasma chamber.