Effect of thruster scaling on pre-sheath and ion-loss region in Hall thrusters

2-D plasma simulation of Hall thrusters based upon a hybrid particle-in-cell method has been conducted and the effect of thruster scaling on the ion-loss region and the degree of ions lost to the channel wall were investigated. The Bohm criterion was utilized for the boundary condition of the insulator wall and a magnetic field with plasma lens focusing was applied in the vicinity of the exit. The calculation results visualize the effects of pre-sheath and ion-loss region, which can be criteria for less-erosion designs. The results of thruster scaling show decreasing trends of the effects of ion-loss region and ion-loss fraction with increasing thruster size, which indicates that less erosion and better thrust efficiency are expected by thruster upsizing.