When two collisionless plasma shells collide, they interpenetrate and the overlapping region may turn Weibel unstable for some values of the collision parameters. This instability grows magnetic filaments which, at saturation, have to block the incoming flow if a Weibel shock is to form. In a recent paper (Bret, J. Plasma Phys., vol. 82, 2016b, 905820403), it was found by implementing a toy model for the incoming particle trajectories in the filaments, that a strong enough external magnetic field $\unicode[STIX]{x1D63D}_{0}$ can prevent the filaments blocking the flow if it is aligned with them. Denoting by $B_{f}$ the peak value of the field in the magnetic filaments, all test particles stream through them if $\unicode[STIX]{x1D6FC}=B_{0}/B_{f}>1/2$ . Here, this result is extended to the case of an oblique external field $B_{0}$ making an angle $\unicode[STIX]{x1D703}$ with the flow. The result, numerically found, is simply $\unicode[STIX]{x1D6FC}>\unicode[STIX]{x1D705}(\unicode[STIX]{x1D703})/\cos \unicode[STIX]{x1D703}$ , where $\unicode[STIX]{x1D705}(\unicode[STIX]{x1D703})$ is of order unity. Noteworthily, test particles exhibit chaotic trajectories.

中文翻译：

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Weibel 细丝中的粒子轨迹：外场倾角和混沌的影响

当两个无碰撞等离子体壳发生碰撞时，它们会相互穿透，重叠区域可能会在某些碰撞参数值下使 Weibel 不稳定。这种不稳定性会生长出磁丝，如果要形成 Weibel 冲击，磁丝在饱和时必须阻止流入的流动。在最近的一篇论文中（布雷特，J.等离子物理学。, 卷。2016 年 82 月b, 905820403)，通过对细丝中的入射粒子轨迹实施玩具模型发现，足够强的外部磁场 $\unicode[STIX]{x1D63D}_{0}$ 如果与它们对齐，可以防止细丝阻塞流动。表示 $B_{f}$ 磁丝中场的峰值，所有测试粒子流过它们，如果 $\unicode[STIX]{x1D6FC}=B_{0}/B_{f}>1/2$ . 在这里，这个结果被扩展到倾斜外场的情况 $B_{0}$ 做一个角度 $\unicode[STIX]{x1D703}$ 随波逐流。结果，从数字上发现，很简单 $\unicode[STIX]{x1D6FC}>\unicode[STIX]{x1D705}(\unicode[STIX]{x1D703})/\cos \unicode[STIX]{x1D703}$ ， 在哪里 $\unicode[STIX]{x1D705}(\unicode[STIX]{x1D703})$ 是有序统一的。值得注意的是，测试粒子表现出混乱的轨迹。