Generation and Control of High Intermittent Heat Load Pattern for Divertor Simulation Studies in GAMMA 10 Tandem Mirror

Development of high power gyrotrons and electron cyclotron heating (ECH) systems for the power modulation experiments in GAMMA 10 have been started in order to generate and control the high heat flux and to make the ELM (edge localized mode) like intermittent heat load pattern for divertor simulation studies. ECH for potential formation at plug region (P-ECH) produces electron flow with high energy along the magnetic filed line. By modulating the ECH power, we can obtain arbitrary pulse heat load patterns. By changing the on/off timing, we can simulate the ELM intermittent heat pulses. The heat flux factor increases almost linearly with ECH power. An intense axial electron flow with energy from hundreds of eV to a few keV generated by fundamental P-ECH is observed. When ECH is turned off, a short burst appears in the end loss ion current due to the axial drain of the confined plasma.