Achieving temporary divertor plasma detachment with MARFE events by pellet injection in the EAST superconducting tokamak
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 trigg...
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| Published in | Plasma science & technology Vol. 19; no. 1; pp. 29 - 35 |
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| Main Author | |
| Format | Journal Article |
| Language | English |
| Published |
IOP Publishing
01.01.2017
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| Subjects | |
| Online Access | Get full text |
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| Summary: | 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. |
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| Bibliography: | divertor, MARFE, pellet injection 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. Guozhong DENG 1,2 Liang WANG1, Xiaoju LIU 1, Yanmin DUAN1, Jiansheng HU1, Changzheng LI1, Ling ZHANG1 ,Shaocheng LIU1, Huiqian WANG1, Liang CHEN1, Jichan XU 1, Wei FENG1, Jianbin LIU1, Huan LIU 1, Guosheng XU1, Houyang GUO1, Xiang GAO 1,2 and the EAST team （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） 34-1187/TL PST-2016-0077 Institute of Plasma Physics |
| ISSN: | 1009-0630 1009-0630 |
| DOI: | 10.1088/1009-0630/19/1/015101 |