Controlled Experiment of Relaxation Processes of Many-Particle System Using Strongly Magnetized Nonneutral Plasma

强磁化纯电子等离子体粒子间的集体相互作用表现为涡旋运动。线状高密度电子群(团)形成高度对称的阵列的现象被称为“涡旋晶体形成”，作为自组织过程的一个典型例子引起了人们的极大关注。尽管学术界有很高的好奇心，但导致有序状态的物理机制还远未完全理解。这个项目的目的一方面是物理地探索自组织过程的每个阶段，另一方面是通过使用强磁场为下一代实验研究建立工具和方法基础。物理理解的主要步骤包括三个成果：(1)团块合并和紧密分离状态之间的分叉被发现严重依赖于在CLU…之间的背景分布中自产生的耗尽带的深度和宽度更多的议员。Soga，Phys.等离子体2003](2)背景布居抑制了团簇的轨道运动，引导它们达到对称构型，最终使它们保持在晶格上。[三佩，Phys.当波的色散满足导体壁和等离子体密度分布施加的径向边界条件时，旋转波场对磁化电子的分布导致密度分布的显著压缩。然而，匹配条件包括密度分布的自调整和共振展宽，这表明耦合外场的等离子体存在另一种类型的自组织。[SOGA，JPFR-SR6 2004]建造了一个可在高达2.2T的强磁场下操作的新的等离子体陷阱，并安装了一个新开发的光学传输系统，用于观察来自弱磁场区域的电子密度分布的精细结构。最适合涡流实验的Malmberg陷阱配置没有显示出限制时间超过200秒。适合于产生Penning平衡的Mohri陷阱组态导致禁闭时间超过500s。长禁闭时间是进一步研究弛豫到平衡或平衡态之间跃迁的基础。该方案成功地为下一代松弛实验研究做好了起点的准备。较少

Collective interactions among particles of strongly magnetized pure electron plasma appear as vortex motion. The phenomena that string-shaped high-density groups (clumps) of electrons form highly symmetric arrays have been coined "vortex crystal formation" and attracting much attention as a representative example of self-organization processes. In spite of high academic curiosity, the physical mechanism leading to the ordered states is far from full understanding. The purpose of this project is to physically explore each stage of the self-organization process on one hand and to build an instrumental and methodical basis for next generation of experimental studies by employing strong magnetic field on the other.Major steps toward physical understanding consist of three achievements : (1) Bifurcation between merger and closely-separated states of clumps is found to critically depend on the depth and width of the depletion belt self-generated in the background distribution between the clu … More mps. [Soga, Phys. Plasmas 2003] (2) The background populations curb the clumps' orbital motion, guide them to symmetric configurations and eventually keep them at the crystal lattice. [Sanpei, Phys. Rev. E (2003)] (3) Application of a rotating wave field to a distribution of magnetized electrons leads to a substantial compression of the density distribution when the dispersion of the wave satisfies the radical boundary conditions imposed by the conducting wall and the plasma density profile. However the matching condition includes self-adjustment of the density profile and resonance broadening, suggesting another type of self-organization of the plasma coupled with external fields. [Soga, JPFR-SR6 2004]A new plasma trap operatable with strong magnetic filed up to 2.2T is constructed together with the installation of a newly developed optical transfer system for observation of fine structures in the electron density distribution from a weal magnetic field zone.[Aoki, JJAP 2004] It has been successfully observed that finer structures are generated under the higher magnetic field. The Malmberg trap configuration, best suited to vortex experiments, has not shown confinement time longer than 200s. The Mohri trap configuration, suited to generate Penning type equilibria, has led to the confinement time exceeding500s. The long confinement time is the basis for the advanced study of relaxation toward equilibrium or transition between equilibrium states. This program has successfully prepared the starting point for the next generation of experimental studies of relaxation. Less