一种考虑电磁波驱动效应的等离子碰撞频率分段计算方法∗

摘要

针对高速飞行器等离子鞘套碰撞频率的经验公式忽略电子-带电粒子碰撞以及电磁波对粒子碰撞的驱动效应对碰撞频率计算的影响问题，提出了一种考虑电磁波驱动效应的碰撞频率分段计算方法。该算法以等离子动力论为基础，综合考虑了电子-中性粒子碰撞、电子-带电粒子碰撞以及电磁波驱动效应对碰撞频率计算的影响，定义了一种新参数—–电离热运动比来判断两类碰撞对碰撞频率计算的影响程度，并根据这一参数值的大小分段计算碰撞频率。理论分析和仿真结果表明：所提出的算法在电离热运动比大于5时比经验公式更接近碰撞频率的真实情况，有助于高速飞行器等离子鞘套碰撞频率的计算和诊断以及电波传播特性的计算。%An empirical formula of collision frequency has been used for years to calculate the collision frequency of aircraft plas-ma sheath. But the formula ignores the influences of electron-electron impact, electron-ion impact, and electro-magnetic (EM) wave driving effect on the collision frequency. To remedy these deficiencies, this paper proposes a segmentation calculation method. Based on the plasma kinetic theory, combined with real flow conditions and synthesizing the influ-ences of electron-electron impact, electron-ion impact and EM wave driving effect together, this method defines a new parameter, ionization-to-thermal motion ratio, to calculate the collision frequency segmentally. Theoretical analysis and simulation results demonstrate that this method is closer to the truth than the empirical formula when ITR is greater than 5.