Statistical Analysis of Type I ELMs at JET

摘要

Edge localised modes (ELMs), MHD phenomena observed at the plasma edge, in H-Mode discharges, are characterised by a sharp increase in the Balmer-alpha (Da) emission. Steady-state H-Mode discharges at JET with neutral beam (NB) heating power well above the H-Mode threshold power have Type I ELMs. Type I ELMs are characterised by increasing ELM frequency with an increase in input power. Steady-state H-Mode experiments with different divertors , viz., Markl, and MarkllA, have been carried out at JET with variations in plasma current, toroidal field, plasma configuration, additional heating and D gas fuelling rate. The results of ELM frequency and diamagnetic energy confinement are presented for Type I ELMs of NBI heated discharges, with and without gas fuelling. The results include percentage change in diamagnetic energy, electron particle density, and plasma current centroid radial movement per ELM. In addition, the time averaged power and density losses as functions of input power and injected particles, respectively, are presented.