论文标题
电子温度各向异性和电子束限制太阳风中的电子动力学不稳定性
Electron Temperature Anisotropy and Electron Beam Constraints From Electron Kinetic Instabilities in the Solar Wind
论文作者
论文摘要
电子温度各向异性和电子束是太阳风中观察到的非平衡电子速度分布的非热特征。在贫困等离子中，这些非平衡分布有望通过波颗粒相互作用受动力学不稳定性调节。这项研究考虑了由核心电子温度各向异性和电子束相互作用驱动的电子不稳定性，并首先对在背景磁场的任意方向上的不稳定性进行了全面分析。它阐明了主要的参数制度（例如，平行核心电子等离子体β$β_ {\ mathrm {ec \ parallel}} $，核心电子温度各向异性$ a _ _ {\ mathrm {ec}}} \ equiv t _ {\ mathrm {ec \ perp}}/t _ {\ mathrm {ec \ Parallel}} $和电子束速度$ v _ {\ mathrm {ebrm {eb}} $的电子不稳定性（e。不稳定性，电磁电子循环基因不稳定性，电子镜不稳定性，电子消防不稳定性和普通模式的不稳定性）。它发现，电子束可以使电子/磁性波不稳定低 - $β_ {\ Mathrm {ec \ parallel}} $制度，以及中等和大的$ $β_ {\ Mathrm {ec \ ec \ parallel Parallel} $ engime的惠斯勒波。它还发现，一种新的斜快磁体/惠斯勒的不稳定是由电子束驱动的，$ v _ {\ mathrm {eb}} \ gtrsim7v _ {\ mathrm {a} $ a _ {\ mathrm {ec}} <1 $。此外，这项研究提出了每种电子不稳定性的电磁反应。这些结果为核心电子温度各向异性和太阳风中的电子束上的电子不稳定性限制提供了全面的概述。
Electron temperature anisotropies and electron beams are nonthermal features of the observed nonequilibrium electron velocity distributions in the solar wind. In collision-poor plasmas these nonequilibrium distributions are expected to be regulated by kinetic instabilities through wave-particle interactions. This study considers electron instabilities driven by the interplay of core electron temperature anisotropies and the electron beam, and firstly gives a comprehensive analysis of instabilities in arbitrary directions to the background magnetic field. It clarifies the dominant parameter regime (e.g., parallel core electron plasma beta $β_{\mathrm{ec\parallel}}$, core electron temperature anisotropy $A_{\mathrm{ec}}\equiv T_{\mathrm{ec\perp}}/T_{\mathrm{ec\parallel}}$, and electron beam velocity $V_{\mathrm{eb}}$) for each kind of electron instability (e.g., the electron beam-driven electron acoustic/magnetoacoustic instability, the electron beam-driven whistler instability, the electromagnetic electron cyclotron instability, the electron mirror instability, the electron firehose instability, and the ordinary-mode instability). It finds that the electron beam can destabilize electron acoustic/magnetoacoustic waves in the low-$β_{\mathrm{ec\parallel}}$ regime, and whistler waves in the medium- and large-$β_{\mathrm{ec\parallel}}$ regime. It also finds that a new oblique fast-magnetosonic/whistler instability is driven by the electron beam with $V_{\mathrm{eb}}\gtrsim7V_{\mathrm{A}}$ in a regime where $β_{\mathrm{ec\parallel}}\sim0.1-2$ and $A_{\mathrm{ec}}<1$. Moreover, this study presents electromagnetic responses of each kind of electron instability. These results provide a comprehensive overview for electron instability constraints on core electron temperature anisotropies and electron beams in the solar wind.
