Dynamic properties of crystallized fine-particle vortices

结晶细颗粒涡的动态特性

基本信息

批准号：
11480105
负责人：
IIZUKA Satoru
金额：
$ 7.68万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

The effects of potential structure and vertical magnetic field on the vortex formation of fine particles are investigated in dc and rf discharge plasmas experimentally.First, we investigate the formation mechanism of fine-particle vortex driven by inhomogeneous potential profile provided by a small plate electrode biased negatively that is placed on a levitation electrode. It is observed that the appearance of vortex phenomena depends on the number of fine particles constituting the fine-particle cloud. The particles are accelerated near the edge of the small electrode. The rotation speed of the vortex varies in radial direction and a shear flow appears with increasing the particle number. On the other hand, when the small electrode potential becomes positive, the fine particles change their flow direction towards the edges of the small electrode. If a cylindrical electrode is used instead of the plate, then the fine particles are absorbed into the cylindrical electrode. This technique is used for fine-particle removal from the dusty plasma.Secondary, we have investigated the driving mechanism of a rotational motion of fine-particle cloud in the presence of vertical magnetic field. We find that changing either density or potential profile in radial direction controls the rotational direction. The ion drag force due to the ion flow in ion-diamagnetic direction takes an important role of the rotation. We also observe a spin motion of fine particle. It is found that the spin axis turns to the magnetic field direction with increasing the magnetic field.

在DC和RF放电等离子体中研究了潜在的结构和垂直磁场对细颗粒涡流形成的影响。首先，我们研究由由小板电极偏置的偏置偏置的偏置偏置的偏置造成的，将其放置在利用电极上的小板电极所提供的细粒子涡流的形成机制。据观察，涡流现象的出现取决于构成细粒子云的细粒子的数量。颗粒在小电极边缘附近加速。涡流的旋转速度在径向方向上变化，并且随着粒子数的增加而出现剪切流。另一方面，当小电极电势变为正时，细颗粒将其流动方向转向小电极的边缘。如果使用圆柱电极代替板，则细颗粒被吸收到圆柱电极中。该技术用于从灰尘等离子体中去除细颗粒。中级，我们研究了在存在垂直磁场的情况下细粒子云的旋转运动的驾驶机理。我们发现在径向方向上更改密度或电势轮廓可以控制旋转方向。由于离子 - 磁磁性方向上离子流动引起的离子阻力作用起着旋转的重要作用。我们还观察到细粒子的自旋运动。发现随着磁场的增加，自旋轴转向磁场方向。