MHD Properties of Low-aspect Ratio RFP in RELAX
MHD Properties of Low-aspect Ratio RFP in RELAX
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DOI：
10.1007/s10894-008-9172-z
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发表时间：
2009-06
影响因子：
1.1
通讯作者：
S. Masamune;A. Sanpei;R. Ikezoe;T. Onchi;Kensuke Oki;T. Yamashita;H. Shimazu;H. Himura;R. Paccagnella
中科院分区：
文献类型：
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作者：
S. Masamune;A. Sanpei;R. Ikezoe;T. Onchi;Kensuke Oki;T. Yamashita;H. Shimazu;H. Himura;R. Paccagnella
低纵横比（A）反向场箍缩（RFP）提供了有吸引力的特性，如增强的自举电流和简单的MHD模式动力学。本文介绍了一台RELAX（REversed field pinch of Low-Aspect ratio eExperiment）实验机，它具有世界上最低的A值2（R/a= 0.5m/0.25m），用于研究低A区的RFP特性。在RELAX装置的平顶低ARFP放电中，等离子体电流约为50 kA，放电持续时间约为2 ms。在等离子体电流为~70 kA的圆顶放电中，观察到了单螺旋模的准周期生长。当主模m = 1/n= 4增长时，环模谱类似于振幅更高的准单螺旋（QSH）RFP态。利用重建程序进行的MHD平衡分析表明，在目前的RELAX等离子体中，自举电流比例低于~5%，如果我们能够在~100 kA的等离子体电流下实现4 × 1019 m − 3的等离子体密度和300 eV的电子温度，自举电流比例将达到~25%。
The low-aspect-ratio (A) reversed field pinch (RFP) offers attractive properties such as enhanced bootstrap current and simpler MHD mode dynamics. The RELAX (REversed field pinch of Low-Aspect ratio eXperiment) machine with the world’s lowestAof 2 (R/a= 0.5 m/0.25 m) has been constructed to explore the RFP properties in low-Aregime. In flat-topped low-ARFP discharges in RELAX, plasma current of ~50 kA has been attained with discharge duration of ~2 ms. In round-topped discharges with plasma current of ~70 kA, quasi-periodic growth of a single helical mode has been observed. When the dominantm= 1/n= 4 mode grows, the toroidal mode spectrum looks like that of the quasi-single helicity (QSH) RFP state with higher amplitude. MHD equilibrium analyses using a reconstruction code have shown that the bootstrap current fraction is lower than ~5% in the present RELAX plasmas, and it will be ~25% if we could achieve the plasma density of 4 × 1019m−3and electron temperature of 300 eV at plasma current of ~100 kA.