Simulation Study on the Dynamics of Dusty Plasmas and the Structure Formation

尘埃等离子体动力学及结构形成的模拟研究

基本信息

批准号：
07680519
负责人：
WATANABE Kunihiko
金额：
$ 1.22万
依托单位：
National Institute for Fusion Science
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07680519/
关键词：
Dusty Plasma Self-organization Simulation Ordered-structure Charging Process Crystalization Dust Grain Coagulation

项目摘要

We have developed a new particle simulation code for dust grains which are dynamically charged by the background plasma. Here, not only the regular attachment effect of the electrons and ions, but also the effects of the secondary electron emission and the coagulation of grains are taken into account.Simulation results show that the all the grains change their charge randomly from negative to positive, or positive to negative in the way of "flio-flop" as the time passes by. The lowest (negative) charge is determined by the balance between the attachment of the electrons and ions, while the highest (positive) charge is determined by the balance between the electron attachment and the secondary electron emission.From the simulation results of various paramenters, it is found that the flip-flop effect is outstanding when the radius of the grains is of the order of 10nm. This is because the attachment of single electron to the grain does not affect much on the surface potential when the ra … More dius of the grain is large enough, say, of the order of the 1 mum. When the radius is small enough, the average probability of the electron attachment becomes small.This fact leads to the another interesting result, namely, the coagulation of a large number of grains, e.g., 1000 grains, make the grain size 10 times larger, so that the flip-flop effect dose not play a major role and grain charge may stay negative.Since the secondary electron emission effect plays a significant role in this simulation, the precise treatment for it is quite important. The secondary electron emission effect would be enhanced more than that given by Sternglas which was employed here, when the grain size is of the order of 10 nm as is treated here.If this enhancement is taken into account, the flip-flop effect shown in the present work becomes more active, even for the larger value of the threshold energy which is assumed here to be a little smaller than the actual one.The dust grains, which are charged in positive or negative, show the coagulation to become larger in size. Because of the above characteristics of the flip-flop effect in the grain size, there exists a probable size of the grains for coagulation. Under the typical parameters of a dust plasma, the most suitable size for the coagulation is found to be of the order of 10nm, which shows a good agreement with the experimental facts. Less

我们为防尘粒开发了一个新的粒子仿真代码，该代码由背景等离子体动态充电。在这里，不仅要考虑到电子和离子的常规依恋效应，还考虑了次级电子发射和晶粒的凝结的效果。拟合结果表明，随着时间的流逝，所有谷物的电荷从随机变为阴性变为正变为正变为正变为阳性，或以“ Flio-flop”的方式变为负。最低（负）电荷取决于电子和离子的附着之间的平衡，而最高（正）电荷取决于电子附着和次级电子发射之间的平衡。从各种牧师的仿真结果，可以发现触发器效应是当晶格的半径为10nm时触发器效应。这是因为当ra…更多的谷物的dius足够大的1个妈妈的顺序时，单个电子对谷物的附着不会对表面电位产生太大影响。当半径足够小时，电子附着的平均概率就会很小。这一事实会导致另一个有趣的结果，即，大量谷物的凝结，例如1000粒，使晶粒尺寸大10倍，使触发器的剂量不起作用，因此对差异的作用可能会产生负面影响，从而对次要的作用产生了重要的作用，这一点很重要，因此重要的是一定的作用。次级电子排放效应将比此处所携带的恒星所给出的二次电子排放效应更大，当晶粒尺寸为10 nm时，此处处理的是10 nm。如果考虑到这种增强，目前工作中所显示的翻转触发效应也会更加活跃，即使在此处均比实际的尘埃呈较大的尘埃呈阳性，即使是较大的灰尘，也会呈现出较大的尘埃。大小更大。由于触发器效应在晶粒尺寸中的上述特征，因此存在有问题的谷物大小以进行凝结。在灰尘等离子体的典型参数下，发现最适合凝结的大小为10nm的阶，这与实验事实显示了很好的一致性。较少的