Implementation of fast switching of the SPARC Runaway Electron Mitigation Coil

The SPARC tokamak's runaway electron mitigation coil (REMC) is an asymmetric, in-vessel coil that is passively driven due to coupling between the plasma and the coil during the current quench of a disruption. As the plasma quenches, the REMC circuit is inductively driven to high (100s of kA) current, providing a perturbing 3D field in addition to the perturbing magnetic fields already present from the disruption dynamics. Past modeling has indicated that the 3D field provided by the REMC deconfines runaway electrons and keeps the runaway electron population at low levels.Transients during the plasma flattop phase and the loop voltage during ramp-up can drive enough current in the coil to negatively impact normal operation, such as instigating locked modes. This necessitates a switch for the REMC circuit that passively actuates during the onset of the current quench. A review of the REMC switch requirements and the switch's impact on the REMC design including in-vessel insulation material requirements to stand off kilovolts of high voltage, radiation protection of sensitive circuit components in a 10^9 cm^2/s neutron environment, and ex-vessel inductance and resistance limitations will be presented.