Selective ion and electron heating and potential formation using mode conversions of ICRF waves in HIEI

Plasma heating and potential formation by ion cyclotron range of frequencies (ICRF) waves are investigated in the HIEI tandem mirror. It is demonstrated that ions and electrons are selectively heated by the appropriate waves that have been mode converted from the fast magnetosonic wave in a two-ion-species plasma. In the central cell, the minority ions can be heated up to 0.3 keV with the presence of the mode-converted slow ion cyclotron wave. Plug cell electrons are heated by the mode-converted electrostatic slow wave resulting in the formation of an ion confining potential. The dependence of the ion confining potential on the plug electron temperature is in qualitative agreement with values predicted by the improved modified Boltzmann relation which includes velocity space diffusion of electrons due to the ICRF wave. The axial confinement of the core plasma is improved by the ICRF produced potential