Experimental analysis of self-organized structure and transport on the magnetospheric plasma device RT-1
Experimental analysis of self-organized structure and transport on the magnetospheric plasma device RT-1
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DOI：
10.1088/1741-4326/ab259a
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发表时间：
2019-07
期刊：
影响因子：
3.3
通讯作者：
M. Nishiura;Z. Yoshida;N. Kenmochi;T. Sugata;K. Nakamura;T. Mori;S. Katsura;K. Shirahata;J. Howard
中科院分区：
文献类型：
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作者：
M. Nishiura;Z. Yoshida;N. Kenmochi;T. Sugata;K. Nakamura;T. Mori;S. Katsura;K. Shirahata;J. Howard
偶极等离子体在场强、密度、温度和其他参数方面表现出强烈的不均匀性，同时保持整体平衡。我们对内部结构的研究揭示了在其最简单的实现形式中起作用的基本自组织机制（如在天文系统中常见的那样）。从RT - 1实验中报告了三个新发现。在实验室系统中首次观测到高能电子核心（类似于行星磁层中的辐射带）的形成。由电子回旋加热产生的高能电子（3 - 15 keV）聚集在位于低密度区域的一个“带”中（通过将高能成分增加到总电子的70%，获得高β值~1）。通过气体注入扰动密度，分析了“上坡扩散”（一种产生密度梯度的自发机制）的动态过程。实验室磁层中自发的密度形成阐明了与行星磁层相关的自组织等离子体输运。相干成像光谱法可视化了离子回旋共振频率加热时离子温度和流速的二维分布。离子温度和流速在整体上得到提高，特别是在悬浮磁体附近沿着磁力线方向。这些结果不仅增进了我们对偶极等离子体中输运和自组织的理解，也增进了我们对与聚变等离子体相关的一般磁约束系统中输运和自组织的理解。
Dipole plasma exhibits strong heterogeneities in field strength, density, temperature and other parameters, while maintaining a holistic balance. Our study of the internal structures reveals the fundamental self-organizing mechanisms operating in their simplest realization (as commonly observed in astronomical systems). Three new findings are reported from the RT-1 experiment. The creation of a high-energy electron core (similar to the radiation belts in planetary magnetospheres) is observed for the first time in a laboratory system. High-energy electrons (3–15 keV), produced by electron cyclotron heating, accumulate in a ‘belt’ located in the low-density region (high-beta value ~1 is obtained by increasing the high-energy component up to 70% of the total electrons). The dynamical process of the ‘up-hill diffusion’ (a spontaneous mechanism of creating density gradient) has been analyzed by perturbing the density by gas injection. The spontaneous density formation in the laboratory magnetosphere elucidates the self-organized plasma transport relevant to a planetary magnetosphere. The coherence-imaging spectroscopy visualized the two-dimensional profiles of ion temperature and flow velocity in the ion cyclotron resonance frequency heating. The ion temperature and flow were enhanced globally, and particularly along the magnetic field lines near the levitation magnet. These results advance our understanding of transport and self-organization not only in dipole plasmas, but in general magnetic confinement systems relevant to fusion plasmas.