Coupling intensity between discharge and magnetic circuit in Hall thrusters Liqiu Wei, Xinyong Yang, Yongjie Ding, Daren Yu and Chaohai Zhang Eur. Phys. J. D, 71 3 (2017) 72 Published online: 23 March 2017 DOI: 10.1140/epjd/e2017-70678-8