ICRF heating experiment on LHD in foreseeing a future fusion device

Plasma heating experiment using the ion cyclotron range of frequencies (ICRF) heating has been carried out. Aiming at the high power and long pulse heating and application to the future fusion device, the antenna without Faraday shield was tested and newly developed antenna, called FAIT antenna, was used. Steady state experiment was progressed by using the high power ICRF heating with those antennas. Plasma discharge length about 48 minutes was achieved with the heating power of 1.2 MW and a line-averaged electron density of 1.2×10¹⁹ m^-3. The injected heating energy reached 3.36 GJ and it is highest in the fusion plasma experiments. We will promote the high power steady state research involving the evaluation of the antennas and heating performance. (author)