Fast parallel Grad–Shafranov solver for real-time equilibrium reconstruction in EAST tokamak using graphic processing unit**Project supported by the National Magnetic Confinement Fusion Research Program of China (Grant No. 2014GB103000), the National Natural Science Foundation of China (Grant No. 11575245), and the National Natural Science Foundation of China for Youth (Grant No. 11205191).

Abstract

To achieve real-time control of tokamak plasmas, the equilibrium reconstruction has to be completed sufficiently quickly. For the case of an EAST tokamak experiment, real-time equilibrium reconstruction is generally required to provide results within 1ms. A graphic processing unit (GPU) parallel Grad–Shafranov (G-S) solver is developed in P-EFIT code, which is built with the CUDA architecture to take advantage of massively parallel GPU cores and significantly accelerate the computation. Optimization and implementation of numerical algorithms for a block tri-diagonal linear system are presented. The solver can complete a calculation within with 65 × 65 grid size and with 129 × 129 grid size, and this solver supports that P-EFIT can fulfill the time feasibility for real-time plasma control with both grid sizes.