Main Causes and Mechanisms of Unexpected Breakdowns of Ion Thruster

Unexpected breakdowns of ion thruster affect its reliability under operating conditions.Upon illustrating the phenomena and consequences of these breakdowns,their main causes,including protrusions on electrode,low-pressure gases,plasma,micro-particles,and insulators,are discussed.Their mechanisms are introduced concerning field emission,low-pressure gas discharge,electrode vaporization and ionization,electron backstreaming,micro-particle impact,cathodic vacuum arc,flashover of insulators,and dielectric breakdown.A summary is given with an outlook on further study of unexpected breakdowns of ion thruster.