Steady-State Solution of a Solar Wind-Generated Electron Cloud in a Lunar Crater

[摘要] We formulate an analytic description of a steady-state electron cloud and affiliated surface charge, formed in the plasma wake generated as the solar wind flows horizontally over a lunar crater. The solution is complementary to the well-known self-similar plasma expansion formulation, which breaksdown at the plasma wake front and thus fails to capture a substantial region of the crater interior. The present model establishes a theoretical basis for existing simulation results, which suggest that the cavity formed below the wake front is populated mainly by electrons, resulting in a substantial negative surface charge. The electrostatic potential throughout this subwake region is determined by solving Poisson'sequation for a Maxwellian electron cloud, bounded above by the self-similar plasma expansion front and below by the electrostatically charged surface.

[发布日期] 2019-07-04

[学科分类] 空间科学

[关键词] CHARGE DISTRIBUTION;ELECTRON CLOUDS;ELECTROSTATIC CHARGE;LUNAR CRATERS;LUNAR SURFACE;PLASMAS (PHYSICS);SOLAR WIND;STEADY STATE;WAKES;WIND VELOCITY