Effect of inhomogeneities on streamer propagation: I. Intersection with isolated bubbles and particles
Effect of inhomogeneities on streamer propagation: I. Intersection with isolated bubbles and particles
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DOI：
10.1088/0963-0252/18/3/035009
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发表时间：
2009-08
影响因子：
3.8
通讯作者：
N. Babaeva;M. Kushner
中科院分区：
文献类型：
--
作者：
N. Babaeva;M. Kushner
高压气体放电中的流光分支和液体中的流光放电几乎是一种普遍的现象，原因有很多。在这篇文章中，我们讨论了一个可能的原因的研究结果--流光通过的介质中的不均匀性。当雪崩锋面遇到它们时，这些不均匀会在电离和激发方面产生相应的增强或减少，其中一些可能会产生分支。研究了三种不均匀现象--负气泡(密度低于周围环境的区域)、正气泡(密度较高)和固体气泡(颗粒)。根据气泡的大小和密度，流光可以聚焦到气泡(负的小气泡)、偏转和分裂(正的气泡和粒子)或折射(大的负气泡)。在气泡的情况下，这种行为的部分原因是负气泡中较大的E/N(电场/气体数密度)，产生更多的电子雪崩电离，而正气泡中较小的E/N，产生较少的电离。由于电子在气泡中的种子通过光电离和随后在大E/N中的雪崩，流光可能会发散成偏离轴线的负气泡。
The branching of streamers in high pressure gas discharges and discharges in liquids is an almost universal occurrence having many causes. In this paper, we discuss results of an investigation of one possible cause—inhomogeneities in the media through which the streamer propagates. These inhomogeneities produce corresponding enhancements or decreases in ionization and excitation as the avalanche front encounters them, some of which may produce branching. Three types of inhomogeneities were investigated—negative bubbles (regions having a lower density than ambient), positive bubbles (having a higher density) and solid bubbles (particles). Depending on the size and density of the bubble, the streamer can be focused into the bubble (negative small bubble), deflected and split (positive bubbles and particles) or refracted (large negative bubble). In the case of gaseous bubbles, this behavior is partly explained by the larger E/N (electric field/gas number density) in the negative bubble, producing more ionization by electron avalanche, and smaller E/N in the positive bubble, producing less ionization. A streamer may diverge into a negative bubble located off axis due to seeding of electrons in the bubble by photoionization and subsequent avalanching in the large E/N.