A hybrid Fluid-Kinetic model based on a polymorphic Particle-in-Cell method is developed for the simulation of plasmas in ion thruster. The numerical scheme is suited for scenarios in which thermal ions or electrons undergo strong acceleration. The polymorphic PIC model is tested for the extraction region of an ion thruster. In this paper, we report the results achieved by implementing the scheme on a single extraction orifice and compare our results with the simulation from known IGUN software for ion extraction.