Nonlinear evolution of the magnetized Kelvin-Helmholtz instability: From fluid to kinetic modeling
2013 (English)In: Physics of Plasmas, ISSN 1070-664X, Vol. 20, no 10, 102118- p.Article in journal (Refereed) Published
The nonlinear evolution of collisionless plasmas is typically a multi-scale process, where the energy is injected at large, fluid scales and dissipated at small, kinetic scales. Accurately modelling the global evolution requires to take into account the main micro-scale physical processes of interest. This is why comparison of different plasma models is today an imperative task aiming at understanding cross-scale processes in plasmas. We report here the first comparative study of the evolution of a magnetized shear flow, through a variety of different plasma models by using magnetohydrodynamic (MHD), Hall-MHD, two-fluid, hybrid kinetic, and full kinetic codes. Kinetic relaxation effects are discussed to emphasize the need for kinetic equilibriums to study the dynamics of collisionless plasmas in non trivial configurations. Discrepancies between models are studied both in the linear and in the nonlinear regime of the magnetized Kelvin-Helmholtz instability, to highlight the effects of small scale processes on the nonlinear evolution of collisionless plasmas. We illustrate how the evolution of a magnetized shear flow depends on the relative orientation of the fluid vorticity with respect to the magnetic field direction during the linear evolution when kinetic effects are taken into account. Even if we found that small scale processes differ between the different models, we show that the feedback from small, kinetic scales to large, fluid scales is negligible in the nonlinear regime. This study shows that the kinetic modeling validates the use of a fluid approach at large scales, which encourages the development and use of fluid codes to study the nonlinear evolution of magnetized fluid flows, even in the collisionless regime.
Place, publisher, year, edition, pages
2013. Vol. 20, no 10, 102118- p.
Current Advance Method, Ion Larmor Radius, Plasma, Simulations, Vortices, Magnetopause, Boundary, Parallel, Schemes, Fields
IdentifiersURN: urn:nbn:se:kth:diva-136511DOI: 10.1063/1.4826214ISI: 000326644100036ScopusID: 2-s2.0-84887252595OAI: oai:DiVA.org:kth-136511DiVA: diva2:676708
FunderEU, FP7, Seventh Framework Programme, 263340, RI-283493, 2012071282
QC 201312062013-12-062013-12-052013-12-06Bibliographically approved