Plasma Breakdown Simulation On EAST Superconductive Tokamak

Breakdown and start-up simulation is an important subject , which plays an instructed role.Enough loop voltage and large null field region is necessary for EAST breakdown and start-up. Due to the individually powered Poloidal field magnets with specially designed compensation coils for the field, currents in each coils have to be adjusted to achieve enough large null field region and desired loop voltage for the breakdown and initial ramp-up..This paper summarized the key factors which influence the plasma breakdown. Particular attention was paid on the eddy current in the current conducting vacuum vessel. Vacuum vessel was divided into 120 elements to model the vacuum vessel for eddy current calculation. This vacuum vessel model together with the coil circuits and plasma consist the model equations for the breakdown calculation. With the additional constrains on the coil current ramp rate, limited maximum voltage and currents, the desired field configuration and loop voltage can be achieved through the solution of the model equations.A comparison between simulation results and actual experiment was given. The comparison showed a good agreement which verified the breakdown model. It is expected such a model can be used for the further breakdown optimization.