复杂结构沿面闪络产生发展阶段模拟研究

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

以天光Ⅱ-A装置X-pinch负载腔为例,采用包含场致发射、二次电子倍增模型的三维模拟软件OPAL,对复杂结构中真空绝缘体沿面闪络的产生与发展阶段进行了模拟研究。模拟结果表明,阳极产生的二次电子在平行于绝缘体表面的电场分量的作用下从阴极座向大半径的运动,是导致沿面闪络的主要原因。并提出了阻断沿面闪络的方法及其原理。采用阻断沿面闪络的措施后,后续多次X-pinch负载腔放电实验证明,正常的回流电流增加了近20%,真空绝缘体上的沿面闪络得到了抑制。

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 extend-ed 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 develop-ment of surface flashover in an X-pinch load case with complex geometry.The discharge experiment shows that the silicon oil coa-ted case has a stronger return current than the not-coated case.Accordingly,possible way of flashover suppression is discussed.