  This paper deals with the numerical resolution of the Vlasov-Poissonsystem
with a strong external magnetic field by Particle-In-Cell(PIC) methods. In this
regime, classical PIC methods are subject tostability constraints on the time
and space steps related to the smallLarmor radius and plasma frequency. Here,
we propose anasymptotic-preserving PIC scheme which is not subjected to
theselimitations. Our approach is based on first and higher order semi-implicit
numericalschemes already validated on dissipative systems. Additionally, when
the magnitude of the external magneticfield becomes large, this method provides
a consistent PICdiscretization of the guiding-center equation, that is,
incompressibleEuler equation in vorticity form. We propose several numerical
experiments which provide a solid validation of the method and its underlying
concepts.
