Controlled Experiment on Self-organization of Many-particle System Using Non-neutral Plasmas

利用新开发的由19个阴极组成的射极阵列，可以产生直径1mm、长度230mm的电子串，我们已经成功地生产出各种形状的电子密度分布，离散的和/或连续的。轴向均质电子弦二维动力学的一个有趣特征是系统动力学等效于不可压缩欧拉流体，电子密度与涡度成正比。将动力学控制与高分辨率和高灵敏度成像技术相结合，我们在涡旋动力学方面取得了一些研究成果。(a)离散电子弦的动力学遵循涡旋弦系统的哈密顿描述。[J.Phys.Soc.Jpn.Lett.Vol.68(1999) 3766。(b)低水平的背景涡度加速了涡旋串之间的合并。(c)涡串沿背景涡分布梯度向上移动。[6](d)初始19根弦的弛豫过程中出现了一系列离散涡阵列的晶体态，表现为随机运动和非弹性碰撞。[1,2,4，待出版](e)背景涡旋分布中枯竭带（空穴）的斑块和环对显著涡旋串的动力学和结晶过程有很强的影响。[1,2,4，待出版](f)实验发现，当系统接近平衡状态时，涡度可以用流函数函数表示。[3]待出版。(g)从实验数据中得到许多统计变量，包括能量、角动量、循环、熵、熵等，并作为时间沿弛豫的函数给出。

With a newly developed emitter array of 19 cathodes for producing electron strings with 1mm in diam. and 230mm in length, we have successfully produced various shapes of electron density distribution, discrete and/ or continuous. An interesting feature of 2-dimensional dynamics of axially homogeneous electron strings is that the system dynamics is equivalent to incompressible Euler fluid and the electron density is proportional to the vorticity. Combining the dynamics control with a high-resolution and high-sensitivity imaging technique, we have achieved several findings on the vortex dynamics.(a) Dynamics of the discrete electron strings follows the Hamiltonian description of the vortex string system. [J.Phys.Soc.Jpn.Lett.Vol.68 (1999) 3766.](b) A low level of the background vorticity accelerates merging between vortex strings.[ibid.](c) A vortex string moves up the gradient of the background vortex distribution. [6](d) A series of crystal states of discrete vortex arrays appear in the relaxation process of the initially 19 strings that show stochastic motions and inelastic collisions.[1,2,4, to be published.](e) Patches and rings of depleted zone (holes) in the background vortex distribution have strong influences on the dynamics of eminent vortex strings and on the process of crystallization.[1,2,4, to be published.](f) The vorticity is found experimentally to be functionally expressed in terms of the stream function as the system approaches to the equilibrium state.[3, to be published.](g) Many statistical variables, including energy, angular momentum, circulation, enstrophy, entropy etc., are obtained from the experimental data and given as a function of time along relaxation.