Study on toroidal current plasmas from RFP to tokamak

从RFP到托卡马克的环形电流等离子体研究

• 批准号: 06044056
• 负责人: YOSHIDA Zensho
• 金额: $ 5.18万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for international Scientific Research
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06044056/
• 关键词: RFP Plasma; ULQ Plasma; Tokamak Plasma; Anomalous Heating; Dynamo Effect; Anomalous Resistance; Fluctuation; Toroidal System; Turbulence; トカマクプラズマ; トアマクプラズマ

Twisted magnetic-field-line structures appear commonly in many different space, astrophysical and laboratory plasmas, and they play an essential role in nonlinear dynamics of these systems. The creation of a magnetic flux rope is an important example of such space phenomena. Magnetic reconnection produce flux tubes with helicalmagnetic-field lines, which stay stable for a period of time. Structural change of the magnetic field is accompanied by energy transfer and transformation, and the relaxation of the magnetic energy results in heating of plasma particles.This research project was planed to explore, based on laboratory plasma experiments, the nonlinear dynamics of "twisted magnetic-field lines" in their most common structure. Using two toroidal experiments, REPUTE-1 (Univ.Tokyo) and EXTRAP-T2 (Alfven Lab.), we produced high-temperature plasmas in the ULQ and RFP regimes. A unique feature of our experiment, in comparison with other laboratory systems, is in that the twist of magneti … More c-field lines is rather tight. A high pitch magnetic field has a large free energy that can excite torsional magnetic fluctuations. In our experiments, we observe clear indications of strong nonlinear effects produced by magnetic fluctuations, which we call the MHD relaxation.The energy dissipation in the MHD relaxation should go much faster than that caused by the resistive dissipation of the mean current. The latter leads the plasma to a diffused state in a long time scale. A different quasi-steady state emerges within a shorter time scale. This bifurcation of a quasi-steady state in a typical "self-organization" of a structure through fluctuations. Enhanced energy dissipation, which is the most essential characteristic of a "dissipative structure", appears as anomalous heating of the plasma. The viscous dissipation heats ions, while the resistive dissipation heats electrons. We observe preferential ion heating in the direction parallel to the magnetic field lines. This observation is consistent to the theoretical prediction of ion viscous dissipation in the self-organization process. Hence, the microscopic mechanism of ion heating associated with the self-organization is now established. Less

扭曲磁场线结构普遍存在于许多不同的空间、天体物理和实验室等离子体中，在这些系统的非线性动力学中起着至关重要的作用。磁通绳的创造就是这种空间现象的一个重要例子。磁重联产生具有螺旋磁场线的磁通管，磁通管在一段时间内保持稳定。磁场的结构变化伴随着能量的传递和转化，磁能的松弛导致等离子体粒子的加热。本研究计划在实验室等离子体实验的基础上，探索“扭曲磁场线”在其最常见结构中的非线性动力学。利用两个环形实验，REPUTE-1 （university . tokyo）和EXTRAP-T2 （Alfven实验室），我们在ULQ和RFP制度下产生了高温等离子体。与其他实验室系统相比，我们实验的一个独特之处在于磁体的扭曲……更多的c场线相当紧密。高间距磁场具有很大的自由能，可以激发扭转磁波动。在我们的实验中，我们观察到磁场波动产生的强烈非线性效应的明显迹象，我们称之为MHD弛豫。MHD弛豫中的能量耗散要比平均电流的电阻耗散快得多。后者使等离子体在长时间尺度上处于扩散状态。一个不同的准稳态在更短的时间尺度内出现。这种分岔的准稳态在一个典型的“自组织”的结构通过波动。增强的能量耗散是“耗散结构”的最基本特征，表现为等离子体的异常加热。粘性耗散加热离子，而电阻耗散加热电子。我们观察到平行于磁力线方向的优先离子加热。这一观测结果与离子自组织过程中粘性耗散的理论预测相一致。由此，建立了离子加热与自组织相关的微观机制。少

项目成果

Z.Yoshida,A.Hasegawa and S.Costa: "Fast Ions Produced by the Kinetic Alfven Wave Turbulence" Comments Plasma Phys.Controlled Fusion. 17. 363-373 (1997)

Z.Yoshida、A.Hasekawa 和 S.Costa：“由动能阿尔文波湍流产生的快离子”评论等离子体物理控制聚变。

Z.Yoshida and S.M.Mahajan: "Perturbation theory for the Alfven wave" International Journal of Modern Phys.B. 9. 2857-2898 (1995)

Z.Yoshida 和 S.M.Mahajan：“阿尔文波的微扰理论”国际现代物理学杂志。

Z.Yoshida: "A Remark on the Hamiltonian Form of the Magnetic-Field Line Equations" Physics of Plasmas. 1. 208-209 (1994)

Z.Yoshida：“关于磁场线方程的哈密顿形式的评论”等离子体物理学。

Z.Yoshida: Iwanami. Mathematical Theory of Collective Phenomena, 303 (1995)

Z.吉田：岩波。

Z.Yoshida and T.Uchida: "Plasma production using energetic meandering electrons" Japanese Journal of Applied Physics. 34. 4213-4216 (1995)

Z.Yoshida 和 T.Uchida：“利用高能蜿蜒电子产生等离子体”日本应用物理学杂志。