A new conservative unsplit method for the solution of the Vlasov equation

We have developed a new conservative method for solving the Vlasov equation without using any splitting technique. Our goal is to maintain the positivity of the distribution function and to avoid un-physical oscillations which might lead to numerical instabilities. Based on a finite volume conservative discretization of the conservative form of the Vlasov equation we implemented a highly accurate second-order upwind scheme. In order to avoid un-physical oscillations and their possible numerical instability we apply a flux-limiter in the second order. We validate our new Vlasov solver by considering standard cases of one-dimensional current-driven ion-acoustic instabilities solving a Vlasov–Ampère set of equations.