F-TRIDYN simulations of tungsten self-sputtering and applications to coupling plasma and material codes

Abstract

Fractal-TRIDYN (F-TRIDYN) is an upgraded version of the Monte Carlo, Binary Collision Approximation code TRIDYN for simulating ion-surface interactions. F-TRIDYN adds an explicit model of surface roughness and additional output modes for coupling to both plasma and material codes. Code-coupling represents a compelling path toward whole-device modeling, especially for future fusion reactors. Whole device models need to span length and time scales of many orders of magnitude. Atomic processes in materials that occur on the order of picoseconds, such as changes to surface morphology, will have an effect on fusion plasma performance over many hours of operational time. Conversely, interactions with the plasma will drive chemical, thermal, and morphological processes in the material. Simulating this complex interaction between the plasma and the plasma-facing material demands fast interfaces between material and plasma codes. F-TRIDYN is a flexible code for simulating atomic-scale ion-surface interactions, which are responsible for interactions between plasma and surface such as sputtering and implantation. F-TRIDYNs surface roughness model allows the effect of surface roughness on ion-surface interactions to be simulated. Surface roughness can significantly alter sputtering yields and other ion-surface interaction quantities. Understanding the role surface roughness plays in Plasma-Material Interactions will be crucial to modeling the performance of future fusion reactors such as ITER. F-TRIDYN is also suited for the simulation of a wider range of plasma-surface interactions where surface morphology may play a role, including those utilized for sputter-coating and plasma treating applications.