Search

The MHD instabilities driven by the energetic-particles are of particular importance for future burning plasma devices, where energetic particles will be abundantly produced by high power heating and fusion reaction. In this paper, some new phenomena induced by high power ECRH are presented. The high frequency (200kHz–350 kHz) instabilities have been observed during the high power ECRH or NBI. The frequencies of the modes are proportional to Alfvén velocity and very close to the TAE frequency in the plasma core. In the lower frequency range from 10 kHz to 35 kHz, the coexistence of multi-mode has also been found during the high power ECRH. The frequencies of the modes are proportional to Alfvén velocity, but much lower than it. Between the two frequency ranges, a new mode with the frequency from 50 kHz to 100 kHz has been observed with high power ECRH and NBI heating together. The modes have obvious frequency chirping within short time, which is the feature of the EPM like modes. The fishbone instability excited by energetic electrons during ECRH has been identified in HL-2A. It is interested to find the frequency jump phenomena in the high power ECRH. The frequency jumps between 8 kHz and 15 kHz within about 25ms periodically, when the power is 1.2MW. The new results are different from the phenomena on Tore-Supra, because the trapped particle dominates in this case.