论文标题
在环境空气中加速，稳定和褪色的负面流媒体的计算研究
A computational study of accelerating, steady and fading negative streamers in ambient air
论文作者
论文摘要
我们使用2D轴对称流体模型研究环境空气中的负流媒体。根据背景电场的不同，我们观察到加速，稳定和褪色的负流媒体。褪色发生在低背景场中，当负流媒体失去场增强时，并且速度与最大电子漂移速度相当时。我们的重点是稳定的繁殖模式，在此过程中，磁带属性（如半径和速度）几乎不会改变。但是，这种模式是不稳定的，从某种意义上说，条件的小变化会导致加速或减速。我们在背景场中观察到稳定的负面流媒体，范围从9.19 kV/cm到15.75 kV/cm，表明没有唯一的稳定传播场（或稳定性场）。另一个发现是，稳定的负流媒体能够继续传播超过数十厘米的人，其头部后方只有有限的导电长度，类似于稳定的正流媒体。在光学直径和磁带速度和彩带头电位等性能之间观察到了大约线性关系。从这些线性关系中，对于稳定的负流媒体的最小光学直径，我们获得了约0.27 mm至0.35 mm的粗糙下限。可以获得稳定的负彩带的最低背景场是9.19 kV/cm。相反，最近在低至4.05 kV/cm的背景场中获得了稳定的正流仪。我们发现，稳定的负和阳性流媒体的性质差异很大。例如，对于稳定的负流媒体，流媒体速度和最大电子漂移速度之间的比率约为2至4.5，而对于稳定的正流仪，该比率范围约为0.05至0.26。
We study negative streamers in ambient air using a 2D axisymmetric fluid model. Depending on the background electric field, we observe accelerating, steady and fading negative streamers. Fading occurs in low background fields, when negative streamers lose their field enhancement and when their velocities become comparable to their maximal electron drift velocities. Our focus is on the steady propagation mode, during which streamer properties like radius and velocity hardly change. However, this mode is unstable, in the sense that a small change in conditions leads to acceleration or deceleration. We observe steady negative streamers in background fields ranging from 9.19 kV/cm to 15.75 kV/cm, indicating that there is no unique steady propagation field (or stability field). Another finding is that steady negative streamers are able to keep propagating over tens of centimeters, with only a finite conductive length behind their heads, similar to steady positive streamers. Approximately linear relationships are observed between the optical diameter and properties like the streamer velocity and the streamer head potential. From these linear relations, we obtain rough lower bounds of about 0.27 mm to 0.35 mm for the minimal optical diameter of steady negative streamers. The lowest background field in which a steady negative streamer could be obtained is 9.19 kV/cm. In contrast, steady positive streamers have recently been obtained in a background field as low as 4.05 kV/cm. We find that the properties of steady negative and positive streamers differ significantly. For example, for steady negative streamers the ratio between streamer velocity and maximal electron drift velocity ranges from about 2 to 4.5, whereas for steady positive streamers this ratio ranges from about 0.05 to 0.26.
