摘要
研究高功率微波作用下等离子体中的雪崩效应,对于研究等离子体防护技术具有重要意义.通过采用等离子体流体近似方法,建立等离子体中的波动方程、电子漂移-扩散方程和重物质传递方程,表征电磁波在等离子体中的传播以及等离子体内部带电粒子的变化情况,分析研究了高功率微波作用下雪崩效应的产生过程和变化规律.研究表明,入射电磁波功率决定了雪崩效应的产生;初始电子密度能够影响雪崩效应产生的时间;入射电磁波的激励作用初始表现为集聚效应,当激励能量积累到一定阈值时,雪崩效应才会产生;在雪崩效应产生过程中,等离子体内部电子密度的变化非常迅速并且比较复杂.雪崩效应产生后,等离子体内截止频率会远超过入射波频率,电磁波不能在等离子体中传播,从而起到防护高功率微波的效果.
High-power microwave（HPM） weapon, which is destructive to electronic systems, has developed rapidly due to the great progress of HPM devices and technologies. Plasma with distinctive electromagnetic characteristics is under advisement as one of potentially effective protection materials. Therefore, research on avalanche ionization effect in plasma caused by the interaction between HPM and plasma is of significance for its HPM protection performance. Based on the method of fluid approximation, the wave equation, the electron drift diffusion equation and the heavy species transport equation, explaining the propagation of microwave and the change of the charged particles inside plasma, are established to study the avalanche ionization effect under the HPM radiation. A two-dimensional physical model is built with the help of software COMSOL according to the plasma protection array designed to disturb the propagation of the HPM pulses. It can be shown that the emergence of avalanche effect is greatly affected by the incident power of microwave, and the generation time would be influenced by the initial electron density. Moreover, it can be observed that the avalanche effect appears only when the plasma array is irradiated for a period of time, which means that the performance of HPM is presented as gathering effect, and a large amount of energy is needed to change the internal particle balance in plasma. In addition, the electron density inside the plasma changes rapidly and complicatedly while the avalanche effect comes into being. Besides, the cutoff frequency of the plasma exceeds the frequency of the incident wave with the increase of electron density, which leads to that the electromagnetic wave cannot propagate in the plasma,so that the plasma can be used to protect the HPM irradiation.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2017年第19期189-196,共8页
Acta Physica Sinica
基金
国家高技术研究发展计划(批准号:2015AA8016029A)资助的课题~~
关键词
电子雪崩效应
等离子体
高功率微波
等离子体防护
avalanche ionization effect, plasma, high-power microwave, plasma protection
