Abstract: Small pr inciple pro to type of Microwave Plasma Thruster ( MPT) has been tested. Follow ing is introducedabout the 100W pow er MPT: system construction, r esonance mo de, distribution of electromagnetic field, couplingbetween electromag netic field, plasma and flow field, complex flow of plasma in nozzle, vacuum plume, performance of prototype and applicat ion prospect of MPT. Some coupled formulae, such as the N-S, Maxwell and Sahaequat ions, ar e introduced when studying the electr omag netic field, t he coupled plasma flow field in r esonance cavity,and the complex flow in nozzle.

Key words: electric propulsion, microwave plasma thruster, electric-magnet field, flow field, orbit transfer