Detection of the free boundary plasma shift in a toroidal helical plasma on Heliotron-E
Detection of the free boundary plasma shift in a toroidal helical plasma on Heliotron-E
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Heliotron-E 上环形螺旋等离子体中自由边界等离子体位移的检测
DOI：
10.1088/0029-5515/35/2/i07
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发表时间：
1995
期刊：
影响因子：
3.3
通讯作者：
T. Obiki
中科院分区：
文献类型：
--
作者：
S. Besshou;K. Ogata;K. Kondo;T. Mizuuchi;K. Nagasaki;H. Okada;F. Sano;H. Zushi;T. Obiki
本文描述了首次成功地实现了螺旋等离子体自由边界位移的磁探测。本文讨论了利用外磁场测量（psi环和调制罗柯夫斯基线圈）确定仿星器中平衡等离子体位移的方法。讨论了最近的实验结果，归一化位移ΔB/ap作为体积平均β β的函数，并与解析和已发表的数值MHD计算结果进行了比较。在标准Heliotron-E组态（Rp = 2.20 m，ap = 0.21 m，i（0）/2π ~ 0.53，i（ap）/2π ~ 2.8）中，当体均β为0.50%时，典型的等离子体边界位移ΔB/ap为（8-10）× 10-3。测得的归一化等离子体边界位移几乎是成比例的抗磁体积平均β，β值高达0.95%。磁场测量的等离子体边界位移ΔB小于3 mm，并将实验观测到的位移（ΔB/ap与βdia的关系）与理论分析的等离子体边界位移进行了比较。测得的偏移位于预期上限（ΔB/ap = β（0）/2βeq）和下限（ΔB/ap= β/2βeq）之间的范围内，其中对于Heliotron-E的标准配置，βeq=[i（ap）/2π]2（ap/Rp）~ 0.77。结果表明，等离子体边界位移的测量值强烈依赖于初始真空磁位形参数，如磁轴的水平位置和旋转变换。当真空磁轴向内移向长轴时，观察到归一化等离子体位移（ΔB/ap）和等离子体感生垂直场的显著减小，这是由于Pfirsch-Schluter电流减小所致
This paper describes the first successful realization of the magnetic detection of the free boundary plasma shift for helical plasmas. A procedure for determining the equilibrium plasma displacement in a stellarator by means of external magnetic field measurements (psi loops and modulated Rogowski coils) is discussed. Recent experimental results, the normalized displacement Δb/ap as a function of volume averaged beta β, are discussed and compared with analytical and published numerical MHD computational results. The typical measured plasma boundary shift, Δb/ap, in the standard Heliotron-E configuration (Rp = 2.20 m, ap = 0.21 m, ι(0)/2π ~ 0.53, ι(ap)/2π ~ 2.8) is (8-10) × 10-3, when the volume averaged beta is 0.50%. The measured normalized plasma boundary shift is nearly proportional to the diamagnetic volume averaged beta, for values of beta up to 0.95%. The magnetically determined plasma boundary shift Δb is less than 3 mm. The experimental observations on shift (Δb/ap versus βdia) are compared with the analytically expected plasma boundary shift. The measured shift lies in the range between the expected upper limit (Δb/ap = β(0)/2βeq) and the lower limit (Δb/ap= β/2βeq), where βeq=[ι(ap)/2π]2(ap/Rp) ~ 0.77 for the standard configuration of Heliotron-E. It is found that the measured plasma boundary shift depends strongly on the initial vacuum magnetic configuration parameters such as the horizontal position of the magnetic axis and the rotational transform. When the vacuum magnetic axis is shifted inward towards the major axis, significant decreases of the normalized plasma shift (Δb/ap) and of the plasma induced vertical field are observed, which are interpreted as being due to a reduction of the Pfirsch-Schluter current
影响因子：
3.3
作者：
A. Gibson;T. Sekiguchi;K. Lackner;S. Bodner;R. Hancox
通讯作者：
A. Gibson;T. Sekiguchi;K. Lackner;S. Bodner;R. Hancox