Summary:
A major advance in magnetic confinement fusion occurred with the discovery of a new operational regime, called the “High confinement mode” (H-mode). The H-mode operation results in a significant increase in the plasma temperature and confinement time.
The significant enhancement in the plasma performance is the result of a transport barrier that forms at the edge of the plasma, normally referred as an “edge transport barrier (ETB)” or a “pedestal”. Typically, the energy content in an H-mode discharge is approximately twice the energy contained in an “Low Confinement mode” (L-mode) discharge, for the plasma heated with the same input power. In addition, H-mode plasma is accompanied by instability, called “Edge localized modes” (ELMs) to limit the growth of the pedestal. An ELM crash is believed to be an magnetohydrodynamic (MHD) activity, triggered by either pressure driven ballooning mode or current driven low-n kink/peeling modes. Recently, several attempts for self-consistently predicting the formation of H-mode and ELMs in Tokamak plasmas has been made using integrated predictive modeling code, such as BALDUR, TASK, ASTRA, and JETTO codes. The details development will be shown and discussed together with the comparison against experimental data from various tokamaks.