Improved modeling for design optimization of cusped field thrusters with support of kinetic analysis

Electric propulsion draws increasing attention in space missions as an alternative to chemical propulsion due to its high efficiency. The cusped field thruster, a class of electrostatic propulsion, is able to operate at different anode voltages and operation points, thereby generating different levels of thrust stably and efficiently. Optimal design points have been selected via multi-objective design optimization with respect to performance measures such as thrust and specific impulse. Particle-in-cell simulation is employed for the selected design points in the present study so as to probe into the physical properties via full kinetic simulation. The influence of the magnet geometry and the resultant magnetic field distribution has been investigated, with particular focus on the effects of the inner/outer magnetic radii and neutralizer current on the plume divergence. The plume divergence has significant impact on the thruster performance. New insights have been gained into the key design factors such as the major influence of the magnet geometry and operating conditions as well as the underlying physical mechanism that crucially accounts for the thruster performance.