Ohmic H-modes in the TCV tokamak

摘要: The TCV tokamak has obtained ohmic H-modes in virtually all diverted plasmas with the ion del B drift directed towards an X-point and several elongated limiter plasmas. Troyon factors (beta(tor)aB/l(p)) up to 2 line average densities 2.2 x 10(20) m(-3), corresponding Greenwald limit, have been ELM-free H-modes. Quasi-stationary lasting for entire current flat top (1.5 s) presence of regular ELMs. occurrence magnitude ELMs found depend on configurational parameters such as position 'active' unbalanced double-null discharges plasma-wall separation single-null discharges. These dependencies permitted active control ELM behaviour TCV. A continuous spectrum amplitudes frequencies observed, ranging from clearly identifiable type III large, low-frequency which expel 12% stored energy 7% particle content are reminiscent I previously unknown, benign kind ELM, a maximum amplitude divertor region, also observed.