Ray-casting based detection of fast ion collision on plasma-facing wall implemented in NuBDeC

To estimate the loss of fast ions in 3D space and the distribution of energy deposition on plasma-facing wall in a fusion reactor, CAD design data of plasma-facing wall and the simulation data of fast ions calculated by NuBDeC developed by KFE are utilized. In particular, we would like to introduce the implementation of the queries of finding a collision point between the plasma-facing wall and the trajectory of plasma particles or determining whether fast ion particles are inside or outside the wall at a specific time. Due to the complexity of the fusion reactor structure, several inefficiencies occur in applying the standard collision detection algorithms to determine the collision between fast ion and the fusion reactor wall. It is expected that the inefficiencies can be managed to some extent by narrowing the scope of the search for the collision points and increasing the efficiency of the collision detection algorithms. To narrow the scope of the collision search, we utilize octree for occlusion. For the efficient collision detection, raycasting or its modified version will be implemented. These methods are considered appropriate for the fast ion trajectory characteristics in fast ion simulation to accelerate the queries implemented in this study. The results of implementation will be discussed. This research was supported by R&D Program of "Development of a unifying grid framework to support physics engines in a virtual fusion reactor (High Performance Fusion Simulation R&D, EN2241-8)" through the Korea Institute of Fusion Energy (KFE) funded by the Government funds. We thank to Simmetrix Inc. providing SimModSuite and SimModeler for educational purposes and appreciate development and distribution of Parallel Unstructured Mesh Infrastructure (PUMI) library by Scientific Computation Research Center (SCOREC) at Rensselaer Polytechnic Institute (RPI)