MOTION OF GASEOUS IONS IN STRONG ELECTRIC FIELDS
MOTION OF GASEOUS IONS IN STRONG ELECTRIC FIELDS
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DOI：
10.1002/j.1538-7305.1953.tb01426.x
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发表时间：
1953-01-01
影响因子：
--
通讯作者：
WANNIER, GH
中科院分区：
文献类型：
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作者：
WANNIER, GH
本文将气体动力学的Boltzmann方法应用于带电粒子在静电场作用下通过气体的运动问题。假设粒子密度很低，离子与原子的碰撞是弹性的，但场是很强的，也就是说，与热能相比，它赋予电荷的能量是不可忽略的。在第一部分中，建立了这一理论的形式框架；场中的运动可以用漂移速度的概念来描述，密度变化的平滑是一个各向异性的扩散过程。在第二部分中，我们详细地讨论了“高场”的情况；对于这种情况，气体分子的热运动可以忽略不计；对于碰撞之间的平均自由时间可以视为与速度无关的情况，方程得到了完全的解；对于离子和分子的极端质量比，也给出了完整的解；特别注意了等质量的情况，这必须用数值方法来处理。在第三部分中，收集了有关“中间场”情况的信息；利用卷积定理解决了平均自由时间不变的情况；除此之外，只有小离子质量(电子)的情况可用。在第四部分中，将第一部分证明的扩散过程推广到数值结果中。第五部分讨论了所取得的成果的范围，并论证了将其半定量地扩展到原来的范围之外的可能性。
This paper applies the Boltzmann method of gaseous kinetics to the problem of charged particles moving through a gas under the influence of a static, uniform electric field. The particle density is assumed to be vanishing low, and the ion-atom collisions are assumed elastic, but the field is taken to be strong; that is the energy which it imparts to the charges is not assumed negligible in comparison to thermal energy. In Part I, the formal framework of such a theory is built up; the motion in the field is describable by the drift velocity concept, and the smoothing out of density variations as an anisotropic diffusion process. In Part II, the “high field” case is treated in detail; this is the case, for which thermal motion of the gas molecules is negligible; the equation is solved completely for the case that the mean free time between collisions may be treated as independent of speed; complete solutions are also presented for extreme mass ratios of the ions and the molecules; special attention is given to the case of equal masses, which has to be handled by numerical methods. In Part III, information about the “intermediate field” case is collected; with the help of a convolution theorem the case of constant mean free time is solved; beyond this, only the case of small ion mass (electrons) is available. In Part IV, the diffusion process, whose existence was proved in Part I, is pushed through to numerical results. Part V discusses the scope of the results achieved and demonstrates the possibility of extending them semiquantitatively beyond their original range.