Experimental Conditions for Electron Bernstein Wave Heating Using EC Waves Injected from High-Field Side in CHS

In the compact helical system (CHS), electron heating by electron Bernstein waves (EBWs) was experimentally investigated to study a technique for high-density plasma heating over cutoff density. The EBWs are excited through a mode conversion process by X-mode waves injected to plasmas from the high-field side. In the experiment, within the range of an oblique EC-wave beam injection angle, evident heating effect was observed. The dependences of the heating effect on the wave's toroidal injection direction and polarization show that the absorption of the mode-converted EBWs should be the cause of the plasma heating effect.