Ion-Cyclotron Resonance Heating Experiment in the Quadruple Minimum-B Field on GAMMA 10

In the GAMMA 10 tandem mirror, Magneto Hydro Dynamic (MHD) stabilization is kept with quadruple minimum-B anchor configuration. In the previous heating experiments, Ion-Cyclotron Range of Frequency (ICRF) antenna installed in the central cell was used for the anchor heating. Fast Alfvén wave excited in the central cell is partly converted to the slow wave in the nonaxisymmetric transition region between the central and the anchor cells, and heats ions in the minimum-B well. In order to produce higher performance plasmas in the central cell, the ion heating should be enhanced in the anchor cell. In this study, an experiment is carried out in the anchor cell to heat ions by ICRF waves without mode conversion. A bar-type antenna is installed in the anchor cell. Applied frequency is adjusted to ion-cyclotron resonance frequency in the minimum-B well. By the additional ion heating with the bar-type antenna, remarkable increase in the diamagnetic signal has been observed in the anchor cell. It is confirmed that the additional heating by the bar-type antenna can also keep MHD stabilization.