Abstract of O-EIRENE Project

Neutral gas physics is a key player in the divertor and the scrape-off layer of magnetically confined plasmas. European edge codes all rely on the EIRENE kinetic Monte Carlo solver to account for this physics. EIRENE is currently MPI parallelized but so far has no shared memory parallelization implemented (OpenMP). This is a strong limitation when coupling to hybrid MPI/OpenMP plasma codes (such as TOKAM3X) and/or using very large grids (e.g. EMC3-EIRENE W7X applications), in which case nodes cannot be fully exploited because of memory limitations. Solving this issue would thus open the way towards more challenging turbulence and/or transport simulations. In the frame of the ongoing thrust 2a E-TASC project led by FZJ (https://users.euro-fusion.org/iterphysicswiki/index.php/TSVVthrust2a), an OpenMP parallelization of the calculation of trajectories is currently implemented at PIIM, without restructuring of the code. This implementation is expected to be verified by the end of 2019, and will serve as a reference point in terms of performance. The next step, for which we request HLST support, is to evaluate how the code could be restructured to gain in performance on this shared parallelization layer.