Impact of lithium wall conditioning and wave-frequency on high density lower hybrid current drive experiment on EAST
Impact of lithium wall conditioning and wave-frequency on high density lower hybrid current drive experiment on EAST
复制标题
锂壁调节和波频率对 EAST 高密度低混合电流驱动实验的影响
DOI：
10.1016/j.nme.2021.100955
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发表时间：
2021-02
影响因子：
2.6
通讯作者：
H.Zhao
中科院分区：
文献类型：
--
作者：
S.G.Baek;M.H.Li;G.M.Wallace;P.T.Bonoli;W.Choi;B.J.Ding;W.Gao;X.Gong;Y.C.Li;S.Lin;L.Meng;F.Poli;S.Shiraiwa;M.Wang;Y.FWang;C.B.Wu;G.H.Yan;L.Wang;Q.Zang;H.Zhao
EAST上一系列专门的低混合电流驱动（LHCD）实验表明，在2.45 GHz和4.6 GHz下，锂壁调节将LH电流驱动和加热扩展到n-e≈4x10 19 m−3的线平均密度。如此高密度的电流驱动对于EAST上长脉冲无感场景的发展至关重要。在锂化过程中，在2.45 GHz频段注入1.5 MW的LH功率导致环路电压下降~ 0.3 V，这与在4.6 GHz频段注入1.1 MW时观察到的环路电压下降相当。观察到的环路电压降低主要归因于射频加热效应。另一项LHCD实验表明，锂壁涂层对刮脱层（SOL）性能的影响比格林沃尔德分数的变化更显著。2.45 GHz的LHCD仍然存在效率损失的问题。发射装置前方增强的功率电离可能导致密度相关波不稳定性的发生。中层SOL密度的增加也可能加速导流器状态的转变，导致x点导流器等离子体中的额外电离和碰撞损失。光线追踪模型支持较低的波频率更容易发生碰撞功率损失。实验证实了锂化是控制SOL等离子体的有用工具，并表明发射器前的密度控制可能是减轻等离子体边界功率损失机制的关键。
A series of dedicated lower hybrid current drive (LHCD) experiments on EAST shows that lithium wall conditioning extends LH current drive and heating up to the line-averaged density of n-e≈ 4x10 19 m− 3 for both 2.45 and 4.6 GHz. Current drive at such a high density is crucial for the development of long-pulse non-inductive scenarios on EAST. With lithiation, the LH power injection of 1.5 MW at 2.45 GHz resulted in a drop of loop voltage of~ 0.3 V, which is a comparable loop voltage drop observed with 1.1 MW at 4.6 GHz. The observed decrease in loop voltage is attributed mostly to the RF heating effect. Another LHCD experiment suggests that lithium wall coating has a more significant impact on the scrape-off-layer (SOL) properties than changes in the Greenwald fraction. LHCD at 2.45 GHz still suffers from a loss of efficiency. Enhanced power ionization in front of the launcher may cause the onset of density-dependent wave instabilities. The rise in the midplane SOL density may also accelerate a transition in the divertor regime, leading to additional ionization and collisional losses in the X-point divertor plasma. Ray-tracing modeling supports that a lower wave frequency is more prone to collisional power loss. The experiments confirm that lithiation is a useful tool to control the SOL plasma, and suggest that density control in front of the launcher may be critical to mitigating power loss mechanisms in the plasma boundary.
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EAST托卡马克中不同发射波频率的低混合电流驱动实验
影响因子：
2.2
作者：
Ekedahl, A.;Hillairet, J.;Goniche, M.;EAST Team
通讯作者：
EAST Team
影响因子：
3.3
作者：
S. Kaye;M. Greenwald;U. Stroth;O. Kardaun;A. Kus;D. Schissel;J. Deboo;G. Bracco;K. Thomsen-K.-Thoms
通讯作者：
S. Kaye;M. Greenwald;U. Stroth;O. Kardaun;A. Kus;D. Schissel;J. Deboo;G. Bracco;K. Thomsen-K.-Thoms
影响因子：
2.2
作者：
J. Huang;X. Gong;A. Garofalo;J. Qian;J. Chen;M. Wu;M. Li;Q. Yuan;Liang Wang;C. Pan-
通讯作者：
J. Huang;X. Gong;A. Garofalo;J. Qian;J. Chen;M. Wu;M. Li;Q. Yuan;Liang Wang;C. Pan-
影响因子：
3.3
作者：
P. Yushmanov;T. Takizuka;K. Riedel;O. Kardaun;J. Cordey;S. Kaye;D. Post
通讯作者：
P. Yushmanov;T. Takizuka;K. Riedel;O. Kardaun;J. Cordey;S. Kaye;D. Post
影响因子：
1.7
作者：
Jeehyun Kim;H. Wi;M. Joung;Sonjong Wang;J. Hillairet
通讯作者：
Jeehyun Kim;H. Wi;M. Joung;Sonjong Wang;J. Hillairet