Predictive Numerical Simulation of ELMy H-mode Discharges for the KSTAR Tokamak

Introduction ELMs (Egde Localized Modes) in the tokamak have strong effects on its divertor conditions with a rapid increase in heat flux, and the pedestal parameters related to ELMs can work as constraints which impact the tokamak edge conditions to determine global confinements [1]. Therefore, a comprehensive understanding of the relations among ELM phenomena, pedestal parameters, and divertor heat conditions is essential for advanced tokamak operations like H-mode discharges. In this paper, the effects of ELMs on divertor heat flux and edge pedestal parameters are found by an integrated core-edge transport simulation for the KSTAR (Korea Superconducting Tokamak Advanced Research) tokamak [2]. Numerical model and simulation results Predictive numerical simulations of ELMy H-mode discharges are carried out for the KSTAR tokamak using an integrated plasma transport code, which has been recently developed in the authors’ laboratory for a simultaneous treatment of core, edge pedestal, and scrape-off layer (SOL) regions of the tokamak [3]. In this integrated modelling, ELMs are supposed to be triggered by ballooning and peeling modes as expressed by the following equations [4, 5]: