Magneto-Fluid Dynamics Seminar
Fourth-order continuum kinetic simulations of instabilities and gyromotion physics in magnetized plasmas
Speaker: Genia Vogman, Lawrence Livermore National Laboratory
Location: Warren Weaver Hall 905
Date: Wednesday, March 3, 2021, 10 a.m.
Synopsis:
Collisionless magnetized plasmas have unique properties. When ion gyromotion scales are comparable to other plasma scales, reduced descriptions based on fluid or gyrokinetic theory are not applicable, and a complete Vlasov-Maxwell or Vlasov-Poisson kinetic treatment is necessary. Characterizing the linear and nonlinear properties of such plasmas requires high-accuracy simulations and equilibrium initial conditions that satisfy the steady-state governing equations. The computational cost of noise-free Vlasov solvers and the lack of equilibria that encapsulate gyromotion physics have made computational studies challenging. This talk will describe how these challenges are addressed through the development of a conservative fourth-order finite-volume Vlasov-Poisson solver and a means of systematically initializing exact kinetic equilibria. Together these techniques, combined with high performance computing, have facilitated comprehensive and targeted investigations of gyromotion physics in 4D(x,y,vx,vy) phase space. The methodology is applied to study the cross-field transport properties of Kelvin-Helmholtz instabilities. Comparisons with single-fluid theory and two-fluid simulations help parse the role of kinetic physics. The study has important implications for cross-field transport in pulsed power inertial confinement fusion experiments, magnetic confinement experiments, and space plasmas.
*This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.