Kinetic study of transverse electron-scale interface instability in relativistic shear flows

Peilin Yao,Wenshuai Zhang,Bao Du,Jianmin Tian,Enhao Zhang,Shaoping Zhu,Xinxin Yan,Xuewu Wang,Hongbo Cai

doi:10.1063/5.0017962

Abstract

Interfacial magnetic field structures induced by transverse electron-scale shear instability (mushroom instability) are found to be strongly associated with electron and ion dynamics, which in turn will influence the development of the instability itself. We find that high-frequency electron oscillations are excited normal to the shear interface. Also, on a larger time scale, the bulk of the ions are gradually separated under the influence of local magnetic fields, eventually reaching an equilibrium related to the initial shear conditions. We present a theoretical model of this behavior. Such separation on the scale of the electron skin depth will prevent different ions from mixing and will thereafter restrain the growth of higher-order instabilities. We also analyze the role of electron thermal motion in the generation of the magnetic field, and we find an increase in the instability growth rate with increasing plasma temperature. These results have potential for providing a more realistic description of relativistic plasma flows.

Highlights

Interfacial magnetic field structures induced by transverse electron-scale shear instability are found to be strongly associated with electron and ion dynamics, which in turn will influence the development of the instability itself
They are closely related to dissipation of plasma kinetic energy into thermal or electromagnetic field energy,8–10 and have been shown to be strongly coupled with other hydrodynamic instabilities such as Rayleigh–Taylor instability (RTI) and Richtmyer–Meshkov instability (RMI),11 often followed by transition to turbulence in highly nonlinear regimes
In astrophysical scenarios such as supernovae and gamma-ray bursts, plasma shear instability has been proposed as a candidate mechanism for strong magnetic field generation along the shear interface,12,13 which cannot be clearly explained by magnetohydrodynamic (MHD) simulations

Summary

INTRODUCTION

Plasma shear instabilities play an important role in a wide range of laboratory and astrophysical plasma flows and in inertial confinement fusion. They are closely related to dissipation of plasma kinetic energy into thermal or electromagnetic field energy, and have been shown to be strongly coupled with other hydrodynamic instabilities such as Rayleigh–Taylor instability (RTI) and Richtmyer–Meshkov instability (RMI), often followed by transition to turbulence in highly nonlinear regimes. In astrophysical scenarios such as supernovae and gamma-ray bursts, plasma shear instability has been proposed as a candidate mechanism for strong magnetic field generation along the shear interface, which cannot be clearly explained by magnetohydrodynamic (MHD) simulations. The coupling of such interfacial electromagnetic fields and charged particles could significantly affect the particle velocity distribution, transport processes within or among species, and the development of instability itself.. Plasma shear instabilities play an important role in a wide range of laboratory and astrophysical plasma flows and in inertial confinement fusion.4–7 They are closely related to dissipation of plasma kinetic energy into thermal or electromagnetic field energy, and have been shown to be strongly coupled with other hydrodynamic instabilities such as Rayleigh–Taylor instability (RTI) and Richtmyer–Meshkov instability (RMI), often followed by transition to turbulence in highly nonlinear regimes.. They are closely related to dissipation of plasma kinetic energy into thermal or electromagnetic field energy, and have been shown to be strongly coupled with other hydrodynamic instabilities such as Rayleigh–Taylor instability (RTI) and Richtmyer–Meshkov instability (RMI), often followed by transition to turbulence in highly nonlinear regimes.4 In astrophysical scenarios such as supernovae and gamma-ray bursts, plasma shear instability has been proposed as a candidate mechanism for strong magnetic field generation along the shear interface, which cannot be clearly explained by magnetohydrodynamic (MHD) simulations..

SIMULATION SETUP AND BASIC PARAMETERS

Single-mode perturbation growth

Thermally induced instability growth

Oscillation of electrons

Separation of ions

SUMMARY