DC Multi-Stage Hybrid Switching Device for Fusion Application

The superconducting coils of modern tokamaks’ electromagnetic systems operate on direct current and are characterized by energy capacities at the level of units and tens of GJ. Initiating and maintaining plasma cord combustion requires unique power levels to both rapidly raise the current in the initial part of the pulse and maintain it in the flat part. Consequently, power supply requirements become almost unrealizable using traditional approaches. In this regard, there is a need for fast-acting DC switching devices capable of switching circuits with currents of tens of kiloamperes.The article describes multistage hybrid switching devices that provide DC switching during plasma discharge initiation in the ITER tokamak. The hybrid circuit breaker is based on electro-pneumodynamically actuated devices that provide arcless current switching to the energy dissipating resistor circuit using a two-stage pulse switch.