In this paper a model of a Radio-Frequency (RF) discharge within a miniature RF ion thruster is presented. This specific type of thruster relies on an inductive discharge producing positive ions that are accelerated by an external electric field in order to produce thrust. The analysis of the particle dynamics within the discharge vessel, as well as the rate of production and loss of the ion species, is then crucial for the determination of the performance of such thrusters. This paper presents the modeling of the bulk plasma within the discharge chamber. A multiphysics approach is taken to characterize the RF discharge within a cylindrical ionization vessel. A finite element model of the discharge is established using COMSOL Multiphysics modeling software. From the input power, mass flow rate, and the properties of xenon, evaluation of the density numbers, electron temperature, and ion current densities are calculated. Simulation values are compared with experimental values obtained with the Miniature RF Ion Thruster (MRIT) being developed.