Steady state current drive by lower hybrid wave in TRIAM-1M tokamak

Long tokamak operation of more than three minutes is demonstrated in the superconducting high field tokamak TRIAM-1M. A steady state plasma with a plasma current of up to 35 kA, a line average density of up to 6x1012cm-3, an ion temperature of 0.5-0.7 keV and an electron temperature of 1.0-1.2 keV was maintained by 2.45 GHz RF power (PRF < 50 kW) alone. Hard X-ray emission profiles indicate that the high energy electrons that carry the steady plasma current are rather concentrated in the inner half-radius region of the plasma column. The time variation of the chromium Kα-line obtained from the soft X-ray spectra suggests that there is little accumulation of metal impurities from the SUS limiter. (author). 3 refs, 7 figs