Experimental conditions for electron Bernstein wave heating by use of EC waves injected from high-field side in CHS

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