Achieving a robust grassy-ELM operation regime in CFETR

doi:10.1088/1741-4326/ab72c0

	Achieving a robust grassy-ELM operation regime in CFETR
	Zhu, Yi-Ren 8; Li, Ze-Yu 1,2,6; Chan, V. S.3,6; Chen, Jia-Le 4; Jian, Xiang 8; Dudson, B. D.5; Garofalo, A. M.6; Snyder, P. B.6; Xu, Xue-Qiao 7; Zhuang, G.3
刊名	NUCLEAR FUSION
	2020-04-01
卷号	60
关键词	grassy-ELMs collisionality high beta(p) peeling-ballooning mode CFETR experimental comparison
ISSN号	0029-5515
DOI	10.1088/1741-4326/ab72c0
通讯作者	Chan, V. S.(chanvs@ustc.edu.cn) ; Zhuang, G.(gezhuang@ustc.edu.cn)
英文摘要	We have identified a robust grassy-edge localized mode (ELM) operation regime for future tokamak reactors. The regime exists within a pedestal top electron collisionality (nu) window at high global poloidal beta (beta(p)). The existence of an upper nu limit for grassy-ELMs is consistent with results previously reported in experiments (Oyama et al 2010 Nucl. Fusion 50 064014), while the existence of a lower nu* limit has not been reported previously. Using EPED and BOUT + +, a theoretical model that quantitatively explains the physics of the grassy-ELMs within the window, which distinguishes them from the small mixed-ELMs at lower nu, is presented for the first time. A peeling-ballooning stability boundary is obtained by scanning the operating density space. The change in density corresponds to a change in nu that affects the pedestal bootstrap current. High beta(p) leads to a strong Shafranov shift, which affects the flux surface averaged pressure drive. The two effects combine to create a peeling-dominated window in intermediate nu* buffered by ballooning-dominated regimes. Only the peeling-dominated regime shows a cyclic behavior in the perturbed pressure during the nonlinear simulation of an ELM crash, reminiscent of grassy-ELM dynamics. Similarly, the energy released across the separatrix is demonstrated to be significantly smaller. The quick recovery of the ELM crash is explainable by the rapid rise of a low n kink-peeling instability when the pedestal current I-ped exceeds a threshold at high beta(p). It minimizes the excursion beyond marginal stability and is absent in the ballooning-dominated regime. Comparison with recent experiments over a range of beta(p) and nu* strongly supports the physical picture proposed by the modeling.
资助项目	National Magnetic Confinement Fusion Program of China[2017YFE0300500] ; National Magnetic Confinement Fusion Program of China[2017YFE0300501] ; National Magnetic Confinement Fusion Program of China[2015GB111001]
WOS关键词	EDGE-LOCALIZED MODES ; H-MODES ; STABILITY ; PEDESTAL ; ENERGY
WOS研究方向	Physics
语种	英语
出版者	IOP PUBLISHING LTD
WOS记录号	WOS:000519027500001
资助机构	National Magnetic Confinement Fusion Program of China
内容类型	期刊论文
源URL	[http://ir.hfcas.ac.cn:8080/handle/334002/103743]
专题	中国科学院合肥物质科学研究院
通讯作者	Chan, V. S.; Zhuang, G.
作者单位	1.Peking Univ, Sch Phys, State Key Lab Nucl Phys & Technol, Beijing 100871, Peoples R China 2.Peking Univ, Fus Simulat Ctr, Beijing 100871, Peoples R China 3.Univ Sci & Technol China, Sch Phys Sci, Dept Engn & Appl Phys, Hefei 230026, Anhui, Peoples R China 4.Chinese Acad Sci, Inst Plasma Phys, Hefei 230031, Peoples R China 5.Univ York, York Plasma Inst, York YO10 5DD, N Yorkshire, England 6.Gen Atom, San Diego, CA 92186 USA 7.Lawrence Livermore Natl Lab, Livermore, CA 94550 USA 8.Huazhong Univ Sci & Technol, State Key Lab Adv Electromagnet Engn & Technol, Wuhan 430074, Peoples R China
推荐引用方式 GB/T 7714	Zhu, Yi-Ren,Li, Ze-Yu,Chan, V. S.,et al. Achieving a robust grassy-ELM operation regime in CFETR[J]. NUCLEAR FUSION,2020,60.
APA	Zhu, Yi-Ren.,Li, Ze-Yu.,Chan, V. S..,Chen, Jia-Le.,Jian, Xiang.,...&Zhuang, G..(2020).Achieving a robust grassy-ELM operation regime in CFETR.NUCLEAR FUSION,60.
MLA	Zhu, Yi-Ren,et al."Achieving a robust grassy-ELM operation regime in CFETR".NUCLEAR FUSION 60(2020).