Comparison Between Fluid Simulation With Test Particles and Hybrid Simulation for the Kelvin‐Helmholtz Instability. Issue 8 (13th August 2019)

• Record Type: Journal Article
• Authors: Ma, Xuanye; Delamere, Peter A.; Nykyri, Katariina; Burkholder, Brandon; Neupane, Bishwa; Rice, Rachel C.
• Is Part Of: Journal of geophysical research. Volume 124:Issue 8(2019)
• Page Start: 6654
• Page End: 6668
• Publication Date: 2019-08-13
• Subjects: Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1029/2019JA026890
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: A quantitative investigation of plasma transport rate via the Kelvin‐Helmholtz (KH) instability can improve our understanding of solar‐wind‐magnetosphere coupling processes. Simulation studies provide a broad range of transport rates by using different measurements based on different initial conditions and under different plasma descriptions, which makes cross literature comparison difficult. In this study, the KH instability under similar initial and boundary conditions (i.e., applicable to the Earth's magnetopause environment) is simulated by Hall magnetohydrodynamics with test particles and hybrid simulations. Both simulations give similar particle mixing rates. However, plasma is mainly transported through a few big magnetic islands caused by KH‐driven reconnection in the fluid simulation, while magnetic islands in the hybrid simulation are small and patchy. Anisotropic temperature can be generated in the nonlinear stage of the KH instability, in which specific entropy and magnetic moment are not conserved. This can have an important consequence on the development of secondary processes within the KH instability as temperature asymmetry can provide free energy for wave growth. Thus, the double‐adiabatic theory is not applicable and a more sophisticated equation of state is desired to resolve mesoscale process (e.g., KH instability) for a better understanding of the multi‐scale coupling process. Key Points: Kelvin‐Helmholtz (KH) vortices in Hall MHD simulation can form large magnetic islands to transport plasma Plasma mixing is mainly through diffusion in hybrid simulation of the KH instability Anisotropic temperature can be formed by the nonlinear KH instability, which can drive kinetic‐scale waves