论文标题
垂直低β冲击中的电子加热
Electron Heating in Perpendicular Low-Beta Shocks
论文作者
论文摘要
无碰撞冲击可在太阳风中，星际爆炸波和热气体渗透的星系簇中的热电子。对电子而不是离子进行了多少冲击加热，哪些等离子体物理控制电子加热？我们使用完全动力学的细胞代码模拟2D垂直冲击。对于磁性马赫数$ \ MATHCAL {M} _ \ MATHRM {MS} \ SIM 1 $ - $ 10 $和PLASMA BETA $β_\ Mathrm {p} \ Lessim 4 $，后浪费的电子/离子温度比率$ t_ \ mathrm $ t_ \ mathrm $ 1 $ {随着$ \ Mathcal {M} _ \ Mathrm {MS} $的增加。在代表性$ \ MATHCAL {M} _ \ MATHRM {MS} = 3.1 $，$β_\ Mathrm {p} = 0.25 $ shock，Electrons在两个步骤中高于绝热压缩的电子热量：离子尺度$ e_ \ e_ \ e_ \ Parallel = \ vec {e} $ \ vec {b} $，然后通过类似两流的不稳定放松。 $ \ vec {b} $ - 平行加热主要是由波诱导的； $ \ vec {b} $ - 垂直加热主要是准静态字段的绝热压缩。
Collisionless shocks heat electrons in the solar wind, interstellar blast waves, and hot gas permeating galaxy clusters. How much shock heating goes to electrons instead of ions, and what plasma physics controls electron heating? We simulate 2-D perpendicular shocks with a fully kinetic particle-in-cell code. For magnetosonic Mach number $\mathcal{M}_\mathrm{ms} \sim 1$-$10$ and plasma beta $β_\mathrm{p} \lesssim 4$, the post-shock electron/ion temperature ratio $T_\mathrm{e}/T_\mathrm{i}$ decreases from $1$ to $0.1$ with increasing $\mathcal{M}_\mathrm{ms}$. In a representative $\mathcal{M}_\mathrm{ms}=3.1$, $β_\mathrm{p}=0.25$ shock, electrons heat above adiabatic compression in two steps: ion-scale $E_\parallel = \vec{E} \cdot \hat{b}$ accelerates electrons into streams along $\vec{B}$, which then relax via two-stream-like instability. The $\vec{B}$-parallel heating is mostly induced by waves; $\vec{B}$-perpendicular heating is mostly adiabatic compression by quasi-static fields.
