Abstract: The plasma accelerator comprises: a main annular channel (24) for ionization and for acceleration defined by parts (22) made of insulating material and open at its downstream end (225); at least one hollow cathode (40) associated with ionizable gas feed means (41); and an annular anode (25) concentric with the main annular channel (24) and disposed at a distance from the open downstream end (225). An annular buffer chamber (23) having a dimension in the radial direction which is greater than that of the main annular channel (24) extends upstream therefrom beyond the zone in which the annular anode (25) is placed. Ionizable gas feed means (26) open out upstream from the anode (25) via an annular manifold (27) into a zone distinct from the zone carrying the anode (25).

Abstract: Internal and external magnetic screens made of magnetic permeable material are added between the discharge chamber and the internal and external sources of magnetic field, respectively. A longitudinal gap is maintained between the screens and their respective internal and external poles, that does not exceed half the distance between the internal and external poles. The exit end part of the internal magnetic screen is placed closer to the middle point of the accelerating channel than the internal pole. The walls of the exit end part of the discharge chamber are constructed with an increased thickness, and extend beyond the planes that the poles lay. The magnetic screens can be located with a gap relative to the magnetic path if connected by a bridge between the screens. The discharge chamber, the anode, and the magnetic system are symmetrically designed relative to two mutually perpendicular longitudinal planes.