Development of novel collision detection algorithms for the estimation of fast ion losses in tokamak fusion device

Abstract

In the quest for a virtual nuclear fusion reactor that can rapidly respond to user demands, we present a study focusing on the development of a fast ion particle collision module and realistic wall modeling using three-dimensional CAD models. The integration of a neutral beam injection code, NuBDeC Rhee et al. (2019) [6] within the Virtual KSTAR platform Kwon et al. (2022) [5] requires efficient detection of the fast ion particle collision events and accurate evaluation of the collision positions on the reactor wall. To achieve this, we investigate six different collision detection algorithms based on the well-known broad and narrow phase framework of collision detection, each utilizing distinct combinations of algorithms based on winding number contour, tri-oval contour, octree, and uniform grid. Furthermore, we explore the utilization of CAD models to create realistic wall surfaces in close resemblance to actual reactor conditions, employing the capabilities of the Unity game engine for mesh-based modeling. Performance tests are conducted, and the total simulation times of the constituent routines are analyzed in comparison. Through this research, in particular, we aim to enhance the reliability and real-time performance of heat load estimation on the plasma-facing components by the neutral beam injection-oriented fast ion losses. The developed fast ion particle collision module and the utilization of realistic wall modeling contribute to improving the authenticity and accuracy of the simulation results.