A stepwise simulation on the random motion of a single cathode spot of vacuum arc

In this paper, a method is proposed to simulate the two-dimensional random motion of a single cathode spot step by step. Simulation parameters, e.g., the characteristic displacement and time step of random motion, are taken from relevant experimental data. In every motion step, the moving direction along the x axis (+x or -x) and y axis (+y or -y) are chose randomly, and the displacements along the x and y coordinates are stochastically independent. Simulation results show that the probability distribution of cathode spot displacement and the average velocity of cathode spot agree well with experimental results, which indicate that the random motion of a cathode spot can be well described by the proposed method. Theoretically speaking, the proposed method also provides a possible approach to simulate the retrograde motion of a cathode spot step by step.