Study on ion energy distribution in low-frequency oscillation time scale of Hall thrustersLiqiu Wei, Wenbo Li, Yongjie Ding, Liang Han, Daren Yu and Yong CaoEur. Phys. J. Plus, 132 11 (2017) 452DOI: https://doi.org/10.1140/epjp/i2017-11714-3