Abstract: A propulsion unit (10) for a spacecraft is described. The propulsion unit (10) comprises a centrally arranged cathode (20), a concentric anode (30), an injection point (60) for injecting a propellant (50) between the central cathode (20) and the concentric anode (30), an acceleration coil system (100) and a vectoring coil system (110) for expelling a plasma plume (75) from a nozzle (115). A plurality of superconducting coils (120, 125) is arranged about the concentric anode (30) for creating a magnetic field (B) between the central cathode (20) and the concentric anode (30) and directing the plasma plume (65) from the nozzle (115).

Abstract: A plasma thruster comprises a cylindrical discharge channel (1), an injector (4), a RF antenna surrounding the discharge channel (1) and a device (3) for generating an axial static magnetic field in the discharge channel (1). The RF antenna is a cylindrical birdcage antenna (2) formed of several electrically conductive parallel legs (10) connected by two end rings (11) including capacitors (12) between adjacent legs (10) in each case. The two end rings (11) with the capacitors (12) are formed on two printed circuit boards (14) to which the legs (10) are attached, said printed circuit boards (14) having a through opening for the discharge channel (1). The antenna maximizes electrical coupling efficiency and provides resulting electromagnetic fields for quasi-neutral plasma acceleration along with the magnetic field effect provided by the externally applied magnetic field.