Modernizing and accelerating fusion plasma turbulence codes targeting exa-scale systems

Asahi, Yuichi   ; Maeyama, Shinya*; Latu, G.*; Garbet, X.*; Watanabe, Tomohiko*; Aoki, Takayuki*; Ogino, Masao*

Under the JHPCN international collaboration with French researchers, we have integrated a kinetic electron model into the kinetic plasma turbulence code GYSELA developed in France. We also explore a performance portable for a kinetic fusion plasma turbulence code like GYSELA. For this purpose, we extract the key features of GYSELA such as the high dimensionality and the semi-Lagrangian scheme, and encapsulate them into a mini-application which solves the simpler version of Vlasov-Poisson system as GYSELA. We implement the mini-app with Open ACC and Kokkos to evaluate the advantages and disadvantages of each approach, from the view point of performance portability, readability and productivity.