Mitigation of type-I ELMs with n = 2 fields on JET with ITER-like wall
Mitigation of type-I ELMs with n = 2 fields on JET with ITER-like wall
复制标题
DOI：
10.1088/0029-5515/53/7/073036
复制
发表时间：
2013-07
期刊：
影响因子：
3.3
通讯作者：
Y. Liang;P. Lomas;I. Nunes;M. Gryaznevich;M. Beurskens;S. Brezinsek;J. Coenen;P. Denner;T. Eich;L. Frassinetti;S. Gerasimov;D. Harting;S. Jachmich;A. Meigs;J. Pearson;M. Rack;S. Saarelma;B. Sieglin;Y. Yang;L. Zeng;J. Contributors
中科院分区：
文献类型：
--
作者：
Y. Liang;P. Lomas;I. Nunes;M. Gryaznevich;M. Beurskens;S. Brezinsek;J. Coenen;P. Denner;T. Eich;L. Frassinetti;S. Gerasimov;D. Harting;S. Jachmich;A. Meigs;J. Pearson;M. Rack;S. Saarelma;B. Sieglin;Y. Yang;L. Zeng;J. Contributors
在具有ITER类壁（ILW）的JET托卡马克上，在H模等离子体中应用n = 2场，观察到I型边缘局域模（ELMs）的减轻。确定了ILW的几个新发现，并与以前的碳壁（C壁）结果进行了对比。先前的结果与C-壁的高碰撞等离子体看到的n = 1或n = 2的领域ELMs的影响很小或没有。然而，ILW最近的观测表明，在n = 2场的应用过程中，频率为1045 Hz的大型I型ELM被高频（10200 Hz）小型ELM所取代。在ILW的情况下，在I型ELMs的强烈缓解期间首次观察到外部撞击点的分裂。偏滤器外板上的最大表面温度（Tmax）达到稳定状态，并且由于小的减缓的ELMs而仅具有几度的小变化。在中等碰撞H-模式等离子体，类似于以前的结果与C-壁，在ELM的频率和密度泵出的增加，观察到在应用程序的n = 2字段。与C壁结果相比，有两个新的观测结果。首先，可以看出，在n = 2磁场的情况下ELM缓解的效果饱和，使得ELM频率不会进一步增加到高于一定水平的n = 2磁扰动。第二，在ELM坠毁过程中，外部撞击点发生分裂，导致偏滤器区域的最大ELM峰值热通量减轻。
Mitigation of type-I edge-localized modes (ELMs) was observed with the application of an n = 2 field in H-mode plasmas on the JET tokamak with the ITER-like wall (ILW). Several new findings with the ILW were identified and contrasted to the previous carbon wall (C-wall) results for comparable conditions. Previous results for high collisionality plasmas with the C-wall saw little or no influence of either n = 1 or n = 2 fields on the ELMs. However, recent observations with the ILW show large type-I ELMs with a frequency of ∼45 Hz were replaced by high-frequency (∼200 Hz) small ELMs during the application of the n = 2 field. With the ILW, splitting of the outer strike point was observed for the first time during the strong mitigation of the type-I ELMs. The maximal surface temperature (Tmax) on the outer divertor plate reached a stationary state and has only small variations of a few degrees due to the small mitigated ELMs. In moderate collisionality H-mode plasmas, similar to previous results with the C-wall, both an increase in the ELM frequency and density pump-out were observed during the application of the n = 2 field. There are two new observations compared with the C-wall results. Firstly, the effect of ELM mitigation with the n = 2 field was seen to saturate so that the ELM frequency did not further increase above a certain level of n = 2 magnetic perturbations. Secondly splitting of the outer strike point during the ELM crash was seen, resulting in mitigation of the maximal ELM peak heat fluxes on the divertor region.