A quasi-neutral one-dimensional hybrid model of a stationary plasma thruster has been used to predict the performance of a laboratory model thruster tested in the Propulsion Ionique pour Vols Orbitaux, Interpretation et Nouvelles Experiences, facility. In this model ions are treated as particles and electrons as a  uid and quasi neutrality is assumed.We describe the calculated efŽ ciencies, thrust, and speciŽ c impulse using xenon and krypton as propellant and their variations as a function of applied voltage and mass  ow rate. Typically, for a voltage of 350 V and an anode mass  ow rate of 5 mg/s, the thrust is on the order of 75 mN for xenon and krypton, and the global efŽ ciency is 40 and 30%, respectively, for xenon and krypton. Although the model is rather simple, the predicted trends are in reasonable agreement with the experimental measurements. The question of doubly charged ions is also examined, and results show that they do not strongly contribute to performance in a stationary plasma thruster-100 Hall thruster.