Destabilization of low-frequency modes (LFMs) driven by a thermal pressure gradient in EAST plasmas with q(min) <= 2
文献类型：期刊论文
| 作者 | Xu, Ming2 ; Ma, Ruirui3; Xu, Liqing2; Li, Yingying1,2; Zhao, Hailin2; Chen, Wei3; Wang, Shouxin2; Li, Guoqiang2; Zhong, Guoqiang2; Wang, Fudi2
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| 刊名 | NUCLEAR FUSION
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| 出版日期 | 2022-12-01 |
| 卷号 | 62 |
| ISSN号 | 0029-5515 |
| 关键词 | low-frequency mode double tearing mode kinetic ballooning mode thermal pressure gradient |
| DOI | 10.1088/1741-4326/ac9292 |
| 通讯作者 | Ma, Ruirui(rrma@swip.ac.cn) ; Xu, Liqing(lqxu@ipp.ac.cn) |
| 英文摘要 | Mode structures and excitation conditions for the low-frequency modes (LFMs) have been investigated in experimental advanced superconducting tokamak (EAST) plasmas with q(min) <= 2. Two different stages/categories of the LFM instabilities are observed during the oscillation of annular/central collapse events: (I) the upward sweeping frequency of LFMs; (II) the upward frequency jumpsof LFMs. The annular/central events are triggered by the m/n = 2/1 double tearing modes with different q-profiles, while the LFMs are characterized by higher mode numbers m/n = 4/2, 6/3, ..., where m and n are the poloidal and toroidal mode numbers, respectively. The maximum radial coverage of the LFMs is located in the annular region of 1.97 <= R <= 2.07 m with the normalized minor radius 0.2 <= rho <= 0.4, while the higher-frequency (or upward sweeping frequency) branch is more localized to the radial position of 2 <= R <= 2.02 m (q(min)). The frequency characteristics of upward sweeps or upward jumps of the LFMs are mainly attributed to the change in the q-profile, e.g. the upward sweeping frequency in stage I is caused by q(min) decreasing. Accordingly, the linear wave properties of LFMs in EAST with weak/reversed magnetic shear are studied numerically and analytically based on a general fishbone-like dispersion relation. Without considering the contribution of energetic ions, it is shown that the LFM with Alfvenic polarization is an MHD-unstable kinetic ballooning mode with frequency of the order of the ion diamagnetic drift frequency. Several important factors for the excitation of LFM instability are analyzed: (1) the role of energetic ions is unimportant, and the LFMs can be excited under the two conditions of with/without energetic ions; (2) the higher tau = T-e/T-i with larger eta(i) = L-ni/L-Ti are required, namely the normalized pressure gradient alpha proportional to (1 + tau)(1 + eta(i)) should be large enough to overcome the stability effect of finite field line bending; (3) the weak/reversed shear q-profile with q(min) <= 2 and suitable S (r/q)(q '')(1/2) are required. |
| WOS关键词 | ALFVEN EIGENMODES ; PREDICTIONS ; EXISTENCE ; PHYSICS |
| 资助项目 | National Nature Science Foundation of China[12175271] ; National Nature Science Foundation of China[12175053] ; National Nature Science Foundation of China[11975267] ; National Magnetic Confinement Fusion Science Program of China[2019YFE03020000] ; National Magnetic Confinement Fusion Science Program of China[2018YFE0304100] |
| WOS研究方向 | Physics |
| 语种 | 英语 |
| 出版者 | IOP Publishing Ltd |
| WOS记录号 | WOS:000873251300001 |
| 资助机构 | National Nature Science Foundation of China ; National Magnetic Confinement Fusion Science Program of China |
| 源URL | [http://ir.hfcas.ac.cn:8080/handle/334002/129863]  |
| 专题 | 中国科学院合肥物质科学研究院 |
| 通讯作者 | Ma, Ruirui; Xu, Liqing |
| 作者单位 | 1.Hebei Key Lab Compact Fus, Langfang 065001, Peoples R China 2.Chinese Acad Sci ASIPP, Inst Plasma Phys, Hefei 230031, Peoples R China 3.Southwestern Inst Phys SWIP, Chengdu 610041, Peoples R China |
| 推荐引用方式 GB/T 7714 | Xu, Ming,Ma, Ruirui,Xu, Liqing,et al. Destabilization of low-frequency modes (LFMs) driven by a thermal pressure gradient in EAST plasmas with q(min) <= 2[J]. NUCLEAR FUSION,2022,62. |
| APA | Xu, Ming.,Ma, Ruirui.,Xu, Liqing.,Li, Yingying.,Zhao, Hailin.,...&Wan, Baonian.(2022).Destabilization of low-frequency modes (LFMs) driven by a thermal pressure gradient in EAST plasmas with q(min) <= 2.NUCLEAR FUSION,62. |
| MLA | Xu, Ming,et al."Destabilization of low-frequency modes (LFMs) driven by a thermal pressure gradient in EAST plasmas with q(min) <= 2".NUCLEAR FUSION 62(2022). |
入库方式： OAI收割
来源：合肥物质科学研究院
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