High Density Plasma Heating by EC-Waves Injected from the High-Field Side for Mode Conversion to Electron Bernstein Waves in LHD  

作　　者：Y.YOSHIMURA S.KUBO T.SHIMOZUMA H.IGAMI H.TAKAHASHI M.NISHIURA S.OGASAWARA R.MAKINO T.MUTOH H.YAMADA A.KOMORI 

机构地区：[1]National Institute for Fusion Science,322-6 Oroshi-cho, Toki 509-5292, Japan [2]Dept. of Energy Science and Technology, Nagoya Univ.,Nagoya 464-8463, Japan

出　　处：《Plasma Science and Technology》2013年第2期93-96,共4页等离子体科学和技术（英文版）

基　　金：supported by KAKENHI (Grant-in-Aid for Scientific Research(C), 21560862) of Japan

摘　　要：To realize an excitation of electron Bernstein waves （EBW） via mode conversion from X-mode waves injected from the high magnetic field side （HFS）, new inner-vessel mirrors were installed close to a helicM coil in the large helicM device （LHD）. 77 GHz electron cyclotron （EC） wave beams injected from an existing EC-wave injection system toward the new mirror are reflected on the mirror so that the beams are injected to plasmas from HFS. Evident increases in the electron temperature at the plasma core region and the plasma stored energy were observed by the HFS beam injection to the plasmas with the line-average electron density of 7.5~ 1019 m-3, which is slightly higher than the plasma cut-off density of 77 GHz EC-waves, 7.35~ 1019 m-3. The heating efficiency evaluated from the changes in the time derivative of the plasma stored energy reached ,,~70%. Although so far it is not clear which is the main cause of the heating effect, the mode-converted EBW or the X-mode wave itself injected from the HFS, an effective heating of high-density plasma over the plasma cut-off of EC-wave was successfully demonstrated.To realize an excitation of electron Bernstein waves （EBW） via mode conversion from X-mode waves injected from the high magnetic field side （HFS）, new inner-vessel mirrors were installed close to a helicM coil in the large helicM device （LHD）. 77 GHz electron cyclotron （EC） wave beams injected from an existing EC-wave injection system toward the new mirror are reflected on the mirror so that the beams are injected to plasmas from HFS. Evident increases in the electron temperature at the plasma core region and the plasma stored energy were observed by the HFS beam injection to the plasmas with the line-average electron density of 7.5~ 1019 m-3, which is slightly higher than the plasma cut-off density of 77 GHz EC-waves, 7.35~ 1019 m-3. The heating efficiency evaluated from the changes in the time derivative of the plasma stored energy reached ,,~70%. Although so far it is not clear which is the main cause of the heating effect, the mode-converted EBW or the X-mode wave itself injected from the HFS, an effective heating of high-density plasma over the plasma cut-off of EC-wave was successfully demonstrated.

关 键 词：electron Bernstein wave EBW slow X-B overdense high density plasmaheating high-field side injection ECH LHD 

分 类 号：TL612[核科学技术—核技术及应用]