I am interested in the numerical resolution of the
Vlasov-Poisson system in a nearly quasineutral regime by Particle-In-Cell (PIC) methods.
In this regime, classical PIC methods are subject to stability constraints on the time and space steps related to the small Debye length and large plasma frequency. I will present an "Asymptotic-Preserving" PIC scheme which is not subject to
these limitations. Additionally, when the plasma period and Debye length are small compared to the time and space steps, this method provides a consistent PIC discretization of the quasineutral Vlasov equation. I will show several one-dimensional numerical experiments which provide a validation of the method and its underlying concepts.