CaDS Seminar 2022 - Nov. 29

Junxian Chew (SDL Plasma Physics)

MPI-OpenMP parallelisation: Townsend avalanche simulation   

Abstract:
Townsend avalanche breakdown is a crucial mechanism for the creation of plasma medium from neutral prefilled gas within a tokamak (magnetic confinement nuclear fusion device), and it is simulated with the help of the Pretty Efficient Parallel Coulomb (PEPC) solver. Townsend avalanche causes an exponential rise of charged particles population, thus presents a numerical challenge when attempting to simulate such phenomenon. In order to handle the exponential growth, there is a need to parallelise all parts of the code to achieve a good scalability in HPC environment. The existing MPI implementation of the electron-neutral collision is now augmented by OpenMP. The implementation resulted in a scalable reduction in compute time per step. The complexities and challenges of the implementation is addressed.