Investigation of fine structure formation of guide field reconnection during merging plasma startup of spherical tokamak in TS-3U
Investigation of fine structure formation of guide field reconnection during merging plasma startup of spherical tokamak in TS-3U
复制标题
TS-3U球形托卡马克合并等离子体启动过程中引导场重联精细结构形成研究
DOI：
10.1088/1741-4326/ab1cdf
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发表时间：
2019
期刊：
影响因子：
3.3
通讯作者：
Ono Y.
中科院分区：
文献类型：
--
作者：
Tanabe H.;Cao Q.;Tanaka H.;Ahmadi T.;Akimitsu M.;Sawada A.;Inomoto M.;Ono Y.
在TS-3和TS-3U高导场托卡马克装置上进行了离子加热输运和磁重联精细结构形成的实验研究。除了先前报道的无中心螺线管高温等离子体启动的演示之外，使用新的96 CH/320 CH超高分辨率2D离子多普勒层析成像诊断技术揭示了重连加热的详细精细结构形成过程。通过使用原位磁探针诊断识别具有中平面上的X点的双轴场配置，详细的测量成功地揭示了离子温度分布形成两种类型的特征加热结构，在X点周围和下游。前者受霍尔效应的影响形成倾斜的加热轮廓，而后者受输运过程的影响形成极向双环状结构。实现的离子加热主要取决于磁场的重联分量，并且在高引导场区域中，引导场对降低加热效率的贡献趋于饱和。在较高引导场的较好环向约束作用下，下游离子加热主要通过平行热传导垂直传输，最终在合并端形成与闭合通量面对齐的极向环状中空分布。
Ion heating/transport and its fine structure formation process through magnetic reconnection have been investigated by high guide field tokamak merging experiments in TS-3 and TS-3U. In addition to the previously reported demonstration of high-temperature plasma startup without center solenoid, the detailed fine structure formation process of reconnection heating has been revealed using new 96CH/320CH ultra-high-resolution 2D ion Doppler tomography diagnostics. By identifying the double-axis field configuration with the X-point on the midplane using in situ magnetic probe diagnostics, the detailed measurement successfully revealed that the ion temperature profile forms two types of characteristic heating structure, both around the X-point and downstream. The former is affected by the Hall effect to form a tilted heating profile, while the latter is affected by the transport process which a forms a poloidal double-ring-like structure. The achieved ion heating mostly depends on the reconnecting component of the magnetic field, and the contribution of the guide field to decrease the heating efficiency tends to be saturated in the high guide field regime. Under the influence of better toroidal confinement with higher guide field, the downstream ion heating is transported vertically, mostly by parallel heat conduction, and finally forms a poloidal ring-like hollow distribution aligned with the closed flux surface at the end of merging.