Simulation study of initialization and development stages of surface flashover in 3D complex structure

The electric field emission and thermal emission around the junction of triple point and the secondary electron emission are believed to play a major role in the initialization and the development stages of the surface flashover. We have extended OPAL, a parallel framework for charged particle optics in accelerator structures and beam lines, with the necessary particle-boundary collision test model, field emission model as well as secondary emission models to simulate the initialization and development of surface flashover in an X-pinch load case with complex geometry. The discharge experiment shows that the silicon oil coated case has a stronger return current than the not-coated case. Accordingly, possible way of flashover suppression is discussed.