Full particle numerical simulations of ion beam neutralization and propagation process for ion thruster

In order to optimize ion thrusters, we investigated the ion-electron coupling in ion beam neutralization process and the physical mechanism of electrically neutral plasma's formation. A two-dimensional axial-symmetry full particle-in-cell method was proposed to numerically simulate the ion beam neutralization process and near-field plume. The results indicate that, a high positive potential is formed in the ion beam near beam source, and it increases with time. The well of potential between this high positive potential and surround environment can limit the escape of electrons, and accelerate ions, making the two kinds of particles to possess the similar velocities, thus, the ion-electron coupling process, namely, the neutralization process, is completed. Additionally, during these processes, the kinetic energies of both electrons and ions increase along the advancing direction of plasma beam, while the electron temperature decreases.