论文标题
在CO $ _2 $和空气中模拟正流媒体：光电离的作用或其他电子资源的作用
Simulation of positive streamers in CO$_2$ and in air: the role of photoionization or other electron sources
论文作者
论文摘要
阳性流媒体排放已在空气中进行了广泛的研究和建模。在这里，我们在有或没有氧气混合物的情况下研究Co $ _2 $中的积极流媒体；它们与当前的高压技术以及金星大气中的排放有关。我们讨论的是，由于相关能量范围内的光子迅速吸收的光子，因此没有有效的光电离心机制以较大的CO $ $ _2 $分数而闻名。因此，正面流媒体只能由于电离锋前的一些其他自由电子来源而传播。因此，我们研究具有不同级别的背景电离的CO $ _2 $中的正流式传播，以提供这些自由电子。用空气中的模拟研究了用背景电离代替光电离的效果。在标准温度和压力为6.4 cm的标准温度和压力下，在背景字段中模拟流媒体，我们发现流媒体传播对光电离或背景电离的水平不敏感。我们还讨论结果不仅取决于崩溃场和应用电场的值，以及预取用或光电离，还取决于电子迁移率$μ（e）$以及有效的电离系数$α_ {\ rm eff}（e）$，它们是电子能量或电场的气体功能。
Positive streamer discharges have been studied and modelled extensively in air. Here we study positive streamers in CO$_2$ with and without oxygen admixtures; they are relevant for current high voltage technology as well as for discharges in the atmosphere of Venus. We discuss that no efficient photoionization mechanism is known for gases with a large CO$_2$ fraction, as photons in the relevant energy range are rapidly absorbed. Hence positive streamers can propagate only due to some other source of free electrons ahead of the ionization front. Therefore we study positive streamer propagation in CO$_2$ with different levels of background ionization to provide these free electrons. The effect of replacing photoionization by background ionization is studied with simulations in air. Simulating streamers in background fields of 16 to 20~kV/cm at standard temperature and pressure within a gap of 6.4~cm, we find that streamer propagation is rather insensitive to the level of photoionization or background ionization. We also discuss that the results depend not only on the value of breakdown field and applied electric field, and on preionization or photoionization, but also on the electron mobility $μ(E)$ and the effective ionization coefficient $α_{\rm eff}(E)$, that are gas-dependent functions of the electron energy or the electric field.
