Enhancement of plasma burn-through simulation and validation in JET

In this paper, new models for a plasma burn-through simulation using the DYON code are introduced in detail, and the quantitative validation of the simulation results against JET data is presented for the first time. In order to calculate the particle confinement time, a dynamic effective connection length model including an eddy current effect is used assuming ambipolar transonic transport and the Bohm diffusion model for parallel and perpendicular particle losses, respectively. Plasma-surface interaction effects are treated with an impurity sputtering yield and an exponential saturation model of the deuterium recycling coefficient. The rate and power coefficients in the Atomic Data and Analysis Structure (ADAS) package are adopted to solve energy and particle balance. The neutral screening effects are taken into account according to particle species, and the sophisticated energy and particle balances are presented. The new burn-through simulation shows good agreement against carbon-wall JET data. This indicates that the burn-through simulation can be applied to investigate the key aspect of physics in plasma burn-through and to perform a predictive simulation for ITER start-up.