Disruption is a major threat to the operation of reactor-grade tokamak devices. To avoid the localization of heat load and excessive electromagnetic force, the disruption mitigation system such as MGI and SPI has been developed. During disruption mitigation, massive impurities cool the plasma edge, causing disturbances in the current density profile and leading to global magnetohydrodynamic (MHD) instabilities. In this study, the electrothermal dynamics of the electron temperature and current density profiles were investigated using the 1.5D disruption simulator INDEX. When one recasts the current diffusion equation into the reaction-diffusion form, the fact that the current density perturbation is driven by the resistivity gradient and curvature is emphasized. The ongoing application of the INDEX code to ASDEX-SPI experiments will also be discussed.
[mehr]