Integrated Modelling of Coupled Free-Boundary Equilibrium and Core-Edge-SOL Transport during Plasma Transients and Applications to ITER SRO Plasma

The ITER High-Fidelity Plasma Simulator (HFPS) is being developed through the integration of a core-edge-SOL transport modelling code, JINTRAC, and a free-boundary equilibrium evolution code, DINA. The HFPS has demonstrated its capability to simulate time-evolving, two-dimensional edge/SOL plasmas by employing a novel scheme that conserves plasma fluid quantities across a sequence of pre-prepared grids corresponding to the prescribed plasma equilibrium evolution. The conservation scheme uses the Leibniz–Reynolds transport theorem combined with a second-order Runge–Kutta method to evaluate residuals in each grid cell and correct deviations between static grid solutions and the time-evolving plasma state.

Recently, the HFPS was enhanced to dynamically generate 2D edge/SOL grids during runtime, aligning with evolving free-boundary equilibrium calculations. In this work, we demonstrate the conservation properties in time-dependent integrated plasma transport simulations of an ITER diverted plasma, where the edge/SOL grids are dynamically generated. The results are compared against simulations performed using static grids and pre-prepared sequential grids. This self-consistent coupling of free-boundary and core-edge-SOL transport, along with improved conservation performance, is applied to the ITER SRO plasmas, including longer-timescale simulations of plasma transients such as plasma current ramp-up and ramp-down.