The effect of cavity density on the formation of electrostatic shock in the lunar wake: 1-D hybrid simulation

作者：Yuan Jin,Ye Pang

摘要：One-dimensional hybrid simulations are carried out to study the plasma refilling process in the lunar wake.Previous theoretical and simulation studies have shown that ion-ion acoustic(ⅡA)instability can be initiated and electrostatic shock can be formed under the condition Te>>Ti.We find that the time evolution ofⅡA instability and the formation of electrostatic shock strongly depend on initial cavity density.The initial position of the electrostatic shock is dependent on the ratio between initial cavity density and background solar wind density,i.e.,the farther away the initial position,the lower is the ratio.When the initial cavity density is low enough,the density and electric field profile across the wake become much complex.Meanwhile,the back-to-back electrostatic shock is unstable in the case of lower cavity densities;at the late evolution stage,a new shock-like structure can be formed at the central region of the lunar wake.

发文机构：Institute of Space Science and Technology School of Information Engineering

关键词：plasmarefillingion-ionacousticinstabilityMoonwakeelectrostaticshock

分类号： O35[理学—流体力学]