Influence of magnetic shielding on electron dynamics characteristics of Penning ion source

The dynamic behaviors of electrons in a miniature Penning ion source model are analyzed by the particle in cell/Monte Carlo collision particle simulation method combined with the scalar magnetic potential finite-difference method. Mainly, the influence of magnetic shielding on the trajectory and spatial distribution of electrons in the discharge process is taken into consideration. The influence of magnetic shielding on the plasma impedance during the excitation discharge of the Penning source is further discussed. The calculated target current is in good agreement with the experimental value. The simulation results show that the addition of magnetic shielding can reduce the fluctuation of electron density, increase the uniformity of electron spatial distribution, and double the plasma impedance stabilization zone, which are beneficial to the stability of the discharge process in the source. However, the magnetic shielding can cause a decrease in the electron density, which limits the plasma ionization degree. The study on magnetic shielding helps to understand the electron dynamics characteristics of the Penning ion source and provides a reference for improving the source performance in the future.