Achieving temporary divertor plasma detachment with MARFE events by pellet injection in the EAST superconducting tokamak  

作　　者：Guozhong DENG Liang WANG Xiaoju LIU Yanmin DUAN Jiansheng HU Changzheng LI Ling ZHANG Shaocheng LIU Huiqian WANG Liang CHEN Jichan XU Wei FENG Jianbin LIU Huan LIU Xiang GAO EAST team 邓国忠;王亮;刘晓菊;段艳敏;胡建生;李长征;张凌;刘少承;汪惠乾;陈良;许吉禅;冯威;刘建斌;刘欢;徐国盛;郭后扬;高翔(Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People＇s Republic of China University of Science and Technology of China, Hefei 230026, People＇s Republic of China)

机构地区：[1]Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China [2]University of Science and Technology of China, Hefei 230026, People's Republic of China

出　　处：《Plasma Science and Technology》2017年第1期29-35,共7页等离子体科学和技术（英文版）

基　　金：supported by National Natural Science Foundation of China(Nos.11575236,11275231,11305206);the National Magnetic Confinement Fusion Science Program of China(Nos.2013GB107003,2014GB106005,2015GB101000)

摘　　要：A new pellet injection system has been equipped on the experimental advanced superconducting tokamak（EAST） in the 2012 campaign,with a pellet size of Ф 2 mm×2 mm,a frequency of1 Hz–10 Hz and velocity of 150 m s^-1–300 m s^-1.The deuterium pellet is well-known for plasma fuelling as well as for triggering the edge localized mode（ELM）.In the 2012 campaign,pellet injection experiments were successfully carried out on EAST.Temporary plasma detachment achieved by deuterium pellets has been observed in a double null（DN） divertor configuration,with multi-pellet injections at a repetition frequency of 2 Hz.The partial detachment of the outer divertors and complete detachment of the inner divertors was achieved after 35 ms of each pellet injection,which have a duration of 30–60 ms with the maximum degree of detachment（DOD） reaching 3.5 and 37,respectively.Meanwhile,the multifaceted asymmetric radiation from the edge（MARFE） phenomena was also observed at the high field side（HFS） near both the lower and upper X-points with radiation loss suddenly increased to about 15%–70%,which may be the main cause of divertor plasma detachment.The temporary detachment induced by pellet injection may act as a new way to study divertor detachment behaviors.A new pellet injection system has been equipped on the experimental advanced superconducting tokamak（EAST） in the 2012 campaign,with a pellet size of Ф 2 mm×2 mm,a frequency of1 Hz–10 Hz and velocity of 150 m s^-1–300 m s^-1.The deuterium pellet is well-known for plasma fuelling as well as for triggering the edge localized mode（ELM）.In the 2012 campaign,pellet injection experiments were successfully carried out on EAST.Temporary plasma detachment achieved by deuterium pellets has been observed in a double null（DN） divertor configuration,with multi-pellet injections at a repetition frequency of 2 Hz.The partial detachment of the outer divertors and complete detachment of the inner divertors was achieved after 35 ms of each pellet injection,which have a duration of 30–60 ms with the maximum degree of detachment（DOD） reaching 3.5 and 37,respectively.Meanwhile,the multifaceted asymmetric radiation from the edge（MARFE） phenomena was also observed at the high field side（HFS） near both the lower and upper X-points with radiation loss suddenly increased to about 15%–70%,which may be the main cause of divertor plasma detachment.The temporary detachment induced by pellet injection may act as a new way to study divertor detachment behaviors.

关 键 词：DIVERTOR MARFE pellet injection 

分 类 号：O53[理学—等离子体物理] TL631.24[理学—物理]