Experimental study of sheath potential coefficient in the J-TEXT tokamak  

作　　者：Wei ZHAO Lin NIE Longwen YAN Min XU Rui KE Jie YANG Zhipeng CHEN Zhanhui WANG Yali WANG J-TEXT Team 赵伟;聂林;严龙文;许敏;柯锐;阳杰;陈志鹏;王占辉;王雅丽;J-TEXT Team(Southwestern Institute of Physics,Chengdu 610041,People's Republic of China;College of Electrical and Electronic Engineering,Huazhong University of Science and Technology,Wuhan 430074,People's Republic of China)

机构地区：[1]Southwestem Institute of Physics,Chengdu 610041,People's Republic of China [2]College of Electrial and Electronic Engineering,Huazhong University of Science and Technology,Wuhan 430074,People's Republic of China

出　　处：《Plasma Science and Technology》2021年第3期51-56,共6页等离子体科学和技术（英文版）

基　　金：supported by the National Key Research and Development Program of China (No. 2018YFE0309103);National Natural Science Foundation of China (Nos. 11875020, 11705052, 11875124 and U1867222);the ITER Organization and China Domestic Agency for the support of this work (ITER5.5.P01.CN.05)。

摘　　要：Sheath potential coefficient α is a key parameter, which is used to estimate plasma potential(Vp)for edge plasma physics study. Recently, a series of experiments has been carried out under hydrogen plasmas in the J-TEXT tokamak with swept probe, which is employed for current–voltage(I–V) characteristic measurement. Electron temperature is evaluated from I–V curve by three-parameter fitting method, and the electron energy probability function shows that electron distribution is Maxwellian both outside and inside of last closed flux surface(LCFS). Plasma potential is obtained by crossing point between I–V exponential fitting curve and electron saturation current extrapolating line, which is in good agreement with first derivative probe technique. The α coefficient profile in the vicinity of the LCFS is obtained, which is in the range of 2.1–3, and decreases from outside to inside of LCFS.

关 键 词：Langmuir probe sheath potential coefficient EEPF 

分 类 号：TL631.24[核科学技术—核技术及应用]