Modeling of macroscopic melt layer splashing during plasma instabilities

Abstract

Damage of plasma-facing components in tokamaks due to various plasma instabilities remains one of the most important problems for successful operation. Macroscopic melt losses from divertor plates and nearby components into core plasma are significant material erosion lifetime and plasma contamination issues. The linear stability analysis and computational modeling are used to predict the onset and growth of surface waves on the plasma–liquid metal interface. The whole course of development, growth, and breakup of waves is modeled for the first time. The new physics mechanism involved in breakdown of a thin melt layer is presented. It is found that the melt layer undergoes macroscopic motion, bulk melt splitting, development and growth of liquid tungsten ligaments that transform to thin threads and eventually break into droplets. These results shed light on the physical behavior of a melt layer under transient plasma instabilities such as edge-localized modes and disruptions.