The invention relates to a cusped
magnetic field plasma thruster. The technical problems to be solved are that a gas working medium cannot be sufficiently ionized at the position of a passageway wallface and cooling of a gas gap between the outer walls of magnets and the inner wall of a
ceramic passageway is slow. In order to solve the technical problems, the thruster comprises an
ionization passageway, permanent magnets, an
anode, a hollow
cathode, magnetic conductive rings, positioning rings and a shell. The longitudinal section of the side wall of the side, along the
ionization passageway,of each permanent
magnet is in a
right trapezoid shape or a rectangular shape, and therefore the inner
diameter, in the direction from the bottom of the
ionization passageway to an outlet, of the ionization passageway is increased in a sequential discrete stair manner. Due to the adoption of the structure, electrons reciprocating between two magnetic tips at a high speed can be sufficiently ionized, and the technical effect that the gas working medium
utilization rate is high is achieved. According to the cusped
magnetic field plasma thruster, by arranging a heat exchange device on the thruster, the temperature of the gas gap between the outer walls of the magnets and the inner wall of the
ceramic passageway is lowered, the paramagnetic phenomenon caused by the fact that temperature of the permanent magnets is too high is avoided, and the service life of the thruster is prolonged.