Global sensitivity analysis for a collisionless plasma using a particle-in-cell method, A

Abstract

Knowing the effects of physical parameters underlying the behavior of plasmas is useful when designing or investigating associated high velocity systems. We use a kinetic model given by the Vlasov-Poisson equations to consider global linear and gradient-based active subspace models that calculate sensitivity metrics related to the phenomena of Landau damping and the two-stream instability. Since analytic results are difficult or impossible to obtain for this system, we use a particle-in-cell method to numerically compute quantities of interest for which the sensitivity metrics can be calculated. In particular, we consider three equilibrium distributions that include Maxwellian and Lorentzian velocity distributions to demonstrate the usefulness of this method in understanding and quantifying parameter effects.