Expansion of Scaling Law of Field-Aligned Potential Difference with Increased Plug ECRH Power in GAMMA 10

Abstract

The high power operation of gyrotrons exceeding their nominal powers has been carried out for ECRH at the plug region in the GAMMA 10 tandem mirror device. The highest recorded value of the axial ion confining potential for a hot ion mode plasma has been obtained. The mean energy Teff of the axially flowing electrons driven by the plug ECRH increases to 3 keV according to the increase in the heating power up to 260 kW. The maximum field-aligned potential difference ∆Φ has reached 5.5 kV and the scaling law between ∆Φ and Teff has expanded.