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MHD simulations of the Kelvin-Helmholtz instability near the ionopause of Venus across a range of density ratios and magnetic Reynolds numbers

MHD simulations of the Kelvin-Helmholtz instability near the ionopause of Venus across a range of density ratios and magnetic Reynolds numbers

Authors :
Xue-ming Li
Yu-mai Cao
Wen-Shan Duan
Xiang-li Wang
Yang Yang
Source :
Astrophysics and Space Science. 366
Publication Year :
2021
Publisher :
Springer Science and Business Media LLC, 2021.

Abstract

The Kelvin–Helmholtz instability on the ionopause of Venus with different density ratios and magnetic Reynolds numbers has been simulated numerically by using the magnetohydrodynamics equations. For the special case of a Venus-like planet, the plasma density increases from the magnetosheath to the ionosphere. The numerical simulation shows that the density increasing toward the planet has more important effects than the magnetic Reynolds number on the Kelvin–Helmholtz instability. And during the evolution of the Kelvin–Helmholtz instability, there are three different phases, the linear growth phase, followed by a nonlinear phase with vortex-like structure, and finally, the turbulent phase. During the nonlinear evolution of the Kelvin–Helmholtz instability, the spatial scale of the vortex has a width of about $\sim 12a$ , where $a$ is the half width of the shear layer located at the Venusian ionopause. For each phase, the vorticity of the system also has different characteristics. Supersonic flow could appear at the position where the vorticity is stronger in both nonlinear and turbulent phases.

Details

ISSN :
1572946X and 0004640X
Volume :
366
Database :
OpenAIRE
Journal :
Astrophysics and Space Science
Accession number :
edsair.doi...........7084dc8bfbc2f1c21ca0b86a1ad7312a
Full Text :
https://doi.org/10.1007/s10509-021-03984-w