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Simulation Research on the Growth Process and Dynamics of Grains in Dusty Plasmas

尘埃等离子体中颗粒生长过程及动力学的模拟研究

基本信息

批准号：
11680493
负责人：
WATANABE Kunihiko
金额：
$ 2.11万
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：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11680493/
关键词：
Dusty plasma Grain Simulation Charging process Coagulation process Fip-flop Ordered structure Self-organization 結晶化

项目摘要

We have developed the simulation code that can pursue the grain dynamics in dusty plasmas, and investigated the charging/coagulation process of the grains. The following results have been obtained. 1) The grains are charged negatively due to the electron attachment, or positively due to the secondary electron or photo-electron emission in the way of flip-flop when the size of the grains and the background plasma temperature are appropriate. 2) Since there exist oppositely charged grains simultaneously in the dusty plasma, they attract and coagulate with each other to grow. 3) The maximum growth of the grains are realized when the grain size is of the order of 10 nm. In the case that the grain size is too small or too large, they will not grow. 4) When the photo-electron emission effect is taken into account, the grains are easily charged in the flip-flop way, and hence coagulate to grow large. Therefore, there can exist very large grains in the space plasma where the photo-electron emission effect is dominant. 5) The grownup grains show the shape of the blue berry. This result agrees with the fact that such grains were observed in the silicon growth experiment in the processing plasmas. 6) When the stationary electric filed is given, the grains are growing up inhomogeneously. Therefore, the largely grown-up grains in the gravitational filed may become distorted. Above results show a good agreement with the experimental results qualitatively and quantitatively. In addition to above simulation research, the virtual reality expression has been also developed in order to investigate the growing process of the grains in detail. It can be observed in the virtual reality system how one grain grows into the shape of the blue berry.

我们开发了能够追踪尘埃等离子体中颗粒动力学的模拟代码，并研究了颗粒的充电/凝固过程。得到了以下结果：1)当晶粒尺寸和背景等离子体温度合适时，晶粒因电子附着而带负电，或因二次电子或光电发射以触发器的方式带正电。2)由于尘埃等离子体中同时存在带相反电荷的颗粒，它们相互吸引、凝聚而生长。3)晶粒尺寸在10 nm量级时，晶粒的生长达到最大。在晶粒尺寸太小或太大的情况下，它们都不会生长。4)考虑到光电子发射效应时，晶粒容易发生翻转带电，从而凝结变大。因此，在光电子发射效应占主导地位的空间等离子体中可以存在非常大的颗粒。成熟的谷粒呈现出蓝莓的形状。这一结果与在加工等离子体中硅生长实验中观察到的结果一致。(6)在给定稳态电场条件下，晶粒生长不均匀。因此，在引力场中长大较大的颗粒可能发生变形。上述结果与实验结果在定性和定量上都有较好的一致性。除了上述仿真研究外，还开发了虚拟现实表达，以便更详细地研究晶粒的生长过程。在虚拟现实系统中可以观察到一粒谷物如何长成蓝莓的形状。