Magnetohydrodynamic behaviour during core transport barrier experiments with ion bernstein wave heating in PBX-M: ELMs, fluctuations and crash events

摘要

If the ion Bernstein wave(IBW)heating power in an H mode discharge of the PBX-M experiment exceeds a threshold power of about 200 kW, a core transport barrier is created in the central region of the plasma. At lower neutral beam injection(NBI)powers, the core barrier is accompanied by an dege L mode. The high edge localized mode(ELM)repetition frequency(1 kHz)prevents the creation of a strong barrier, so the edge first has to make an H-to-L transition before a strong core transport barrier can be created. At higher NBI powers, the ELM repetition frequency is lowered to less than 200 Hz, which allows the immediate creation of strong core barrier.