AC losses in a Tokamak

Problem statement A Tokamak is a fusion machine where a plasma is heated by a pulsed magnetic field. To achieve high field levels superconducting magnets must be used. However superconductor have so called AC losses during pulses. Our taks is to compute these losses during a typical field swing. Modelling The loop primitive of M'C has been used to generate this model of the Poloidal Field system of the International Experimental Thermonuclear Reactor (ITER). In a tokamak two magnetic systems are present, a pulsed poloidal field system, and a steady toroidal field system. Because we are mostly concerned about the pulsed system, we choose to neglect the toroidal field system (not represented here).

Results

This is the map of AC loss in the cross section of one of the divertor coils (the upmost coil, in green in the plot above). Color coding is from high loss (red) to low loss (blue). The loss in the coil cross section peaks at the coil inner radius, where the field change rate is maximum. Note the slight top/bottom asymmetry, higher losses are generated close to the machine central solenoid which is swinging at a high field change rate