摘要航天飞行器以高超音速再次进入大气层时，剧烈的空气摩擦导致其周围空气和表面材料发生热电离，形成一定厚度的等离子层，即等离子鞘套。等离子鞘套会反射，散射或吸收电磁波，造成通信信号衰减，严重时还会导致通信中断现象，即通信黑障。而此时飞行器须与在轨卫星和地面控制中心进行通信，如GPS导航定位，遥感遥控，语音通信等。通信黑障的发生必将给飞行器的实时控制和安全性造成不良影响。78582

对于如何抑制通信黑障的研究需要对等离子体特性进行研究。由于高空实验操作复杂、难度大、费用昂贵且重复性低，实验证明，可用低气压辉光放电来产生等离子体模拟类似效应。相比于实验，数值模拟在研究辉光放电有着不可忽视的优势。本文运用流体模型，利用COMSOL Multiphysics仿真软件模拟了低气压辉光放电现象，分析了所产生的等离子体的相关特性，结果表明通过增大气压或提高交流电源频率的方法可以有效提高等离子体的电子密度。

毕业论文关键词  低气压辉光放电，等离子体，数值模拟，流体模型，气压，频率，电子密度

毕业设计说明书外文摘要

Title    The simulation and analysis of low pressure glow discharge                 

Abstract When hypersonic spacecraft reenter into the atmosphere, severe air friction leads to thermal ionization of its surface material and surrounding air and then form a plasma layer , namely plasma sheath。 Plasma sheath will reflect, absorb or scatter electromagnetic waves, resulting in attenuation of communication signal even disruption of communication, namely communication blackout。 By this time the aircraft is communication with satellites and ground control center, such as GPS navigation, remote sensing, and voice communications。 Communications blackout will cause adverse effects to real-time control and safety of the astronauts。

To inhibit the communication blackout,it is needed to study the characteristics of plasma。Because high altitude experimental is complex,difficult, expensive and there are experiments that show the fact that it is available to use low-pressure glow discharge to generate plasma and then simulate the analogous effect。 Compared with experiment, numerical simulation have obviously advantages。 In this paper, I use COMSOL Multiphysics simulation software to simulate the phenomena of low-pressure glow discharge through fluid model。The analysis of the relevant characteristics of the plasma indicate that the electron density of plasma can be effectively improved by increasing air pressure or the frequency of the AC power。

Keywords  Low pressure glow discharge, Plasma, Numerical simulation, Fluid model Atmospheric pressure, Frequency，Electron density

目次

1绪论1

1。1研究背景1

1。2低温等离子体研究现状··2

1。3论文主要结构·3

2气体放电基本理论分析··4

2。1气体放电的历史回顾·4

2。2辉光放电4

2。3汤生放电原理简介··7

2。4气体放电的着火条件·9

2。5碰撞理论简介·10

3等离子体概述·12

3。1等离子体简介·12

3。2等离子体的分类12

3。3低温等离子体的应用13

3。4低温等离子体的产生14

3。5低温等离子体物理研究现状及面临问题·17