论文标题
密度跳跃是磁场的函数，用于对等离子体的切换无碰撞冲击
Density jump as a function of magnetic field for switch-on collisionless shocks in pair plasmas
论文作者
论文摘要
无碰撞冲击的特性，例如密度跳跃，通常源自磁流失动力学（MHD），其中假定各向同性压力。然而，在无碰撞等离子体中，外部磁场可以维持稳定的各向异性。在\ cite {bretjpp2018}中，我们通过冲击锋设计了一个用于血浆的动力学历史的模型，从而可以自言自语地计算下游各向异性，因此，在上游参数方面，密度跳跃。该模型处理了平行冲击的情况，其中磁场在上游和下游的前部正常。然而，MHD还允许进行冲击解决方案，即所谓的开关解决方案，该解决方案仅在上游的前面与前部正常。本文包括将我们的模型应用于这些切换的冲击。尽管MHD在有限的Alfvén马赫数字范围内仅提供1个切换解决方案，但我们的型号在略有不同的AlfvénMach数字范围内提供了2种解决方案。这两种解决方案很可能是我们模型下中间和快速MHD冲击的结果。尽管中间和快速冲击在MHD中合并为平行情况，但它们不在我们的模型中。为简单起见，形式主义仅限于上游冷的对等离子中的非相关性冲击。
The properties of collisionless shocks, like the density jump, are usually derived from magnetohydrodynamics (MHD), where isotropic pressures are assumed. Yet, in a collisionless plasma, an external magnetic field can sustain a stable anisotropy. In \cite{BretJPP2018}, we devised a model for the kinetic history of the plasma through the shock front, allowing to self-consistently compute the downstream anisotropy, hence the density jump, in terms of the upstream parameters. This model dealt with the case of a parallel shock, where the magnetic field is normal to the front both in the upstream and the downstream. Yet, MHD also allows for shock solutions, the so-called switch-on solutions, where the field is normal to the front only in the upstream. This article consists in applying our model to these switch-on shocks. While MHD offers only 1 switch-on solution within a limited range of Alfvén Mach numbers, our model offers 2 kinds of solutions within a slightly different range of Alfvén Mach numbers. These 2 solutions are most likely the outcome of the intermediate and fast MHD shocks under our model. While the intermediate and fast shocks merge in MHD for the parallel case, they do not within our model. For simplicity, the formalism is restricted to non-relativistic shocks in pair plasmas where the upstream is cold.
