Particle-in-cell methods in predicting materials behavior during high power deposition

Abstract

AbstractLarge energy fluxes and energy deposition are often found during off normal events in fusion reactors both magnetic and inertial confinement. Great temperature excursions can be found in the plasma facing components materials resulting in melting, evaporation, and expansion of the target material vapor cloud and successive plasma interaction. A general methodology for the computational solution of this very complex problem is proposed in this paper using a novel approach of the Particle-in-Cell method. This novel approach preserves many of the original Particle-in-Cell methodology proposed by Harlow's but introduces several changes to the method, which makes it particularly suitable in plasma dynamics applications as Tokamaks devices. Benchmarking is done using results from the very well-known and benchmarked HEIGHTS computer package and using available results from the MK200 plasma gun experiments. The general scheme is explained in detail and results and discussion related to the main computational aspects are presented. In particular, the critical importance of the starting computational mesh versus the aimed accuracy is studied and explained. The methodology is different from any other presented in literature because the dynamics of the physical problem dictates that as enough energy is being dumped on the target plate, melting and evaporation of the material takes place. As time progresses, new sample particles are introduced in the system making this boundary a dynamic one along time. Computer time is discussed in relation to the initial sample particle loading, aimed accuracy and importance of the time used for solving the radiation transport at each time step.