Core Confinement Optimisation Using Nonlinear Simulations

The heat confinement in a toroidal axisymmetric plasma is optimised using the CoRFU framework. This incorporates Trinity transport calculations which include full nonlinear turbulent transport simulations. These are carried out using GRYFX, a GPU-based hybrid-gyrofluid code which includes a gyrokinetic treatment of the zonal flows, and novel closures to model perpendicular phase mixing. Starting from a simple oval equilibrium, the elongation and triangularity of the outer flux surface are varied by the algorithm to optimise the fusion power per unit volume. This performance metric is increased by 91% during the simulation.