A Fully Kinetic Perspective of Electron Acceleration around a Weakly Outgassing Comet
A Fully Kinetic Perspective of Electron Acceleration around a Weakly Outgassing Comet
复制标题
弱排气彗星周围电子加速的全动力学视角
DOI：
--
复制
发表时间：
2020
影响因子：
4.9
通讯作者：
S. Markidis
中科院分区：
文献类型：
--
作者：
A. Divin;J. Deca;A. Eriksson;P. Henri;G. Lapenta;V. Olshevsky;S. Markidis
彗星任务罗塞塔显示存在高于预期的超热电子通量。在这项研究中，我们使用太阳风与彗星相互作用的 3D 全动力学电磁模拟，限制了导致体电子激发的动力学机制，该体电子激发从太阳风电子的温暖背景中产生超热分布。我们识别并表征了磁场对齐的双极电场，该电场确保准中性并捕获热电子。太阳风电子在彗核附近被加速到高达 50-70 eV 的能量，无需波粒或湍流加热机制。我们发现加速电势控制平行电子温度、总密度以及（在较小程度上）垂直电子温度和磁场强度。我们的自洽方法使我们能够更好地了解控制近彗星等离子体环境的基本等离子体过程。
The cometary mission Rosetta has shown the presence of higher-than-expected suprathermal electron fluxes. In this study, using 3D fully kinetic electromagnetic simulations of the interaction of the solar wind with a comet, we constrain the kinetic mechanism that is responsible for the bulk electron energization that creates the suprathermal distribution from the warm background of solar wind electrons. We identify and characterize the magnetic field-aligned ambipolar electric field that ensures quasi-neutrality and traps warm electrons. Solar wind electrons are accelerated to energies as high as 50–70 eV close to the comet nucleus without the need for wave–particle or turbulent heating mechanisms. We find that the accelerating potential controls the parallel electron temperature, total density, and (to a lesser degree) the perpendicular electron temperature and the magnetic field magnitude. Our self-consistent approach enables us to better understand the underlying plasma processes that govern the near-comet plasma environment.