Patent ID: 8129913

Claim:
A closed electron drift thruster comprising: a main annular ionization and acceleration channel about an axis of the thruster; at least one hollow cathode; an annular anode concentric about the main annular channel; a pipe and a manifold for feeding the anode with ionizable gas; and a magnetic circuit for creating a magnetic field in said main annular channel; said magnetic circuit comprising: at least one axial magnetic core surrounded by a first coil and by an inner upstream pole piece forming a body of revolution; and a plurality of outer magnetic cores surrounded by outer coils; wherein said magnetic circuit further comprises an essentially radial outer first pole piece defining: a concave inner peripheral surface; and an essentially radial inner second pole piece defining a convex outer peripheral surface; and wherein said concave inner peripheral surface and said convex outer peripheral surface present respective adjusted profiles that are distinct from circular cylindrical surfaces so as to form between them a gap of varying width presenting zones of maximum value in register with the outer coils, and zones of minimum value in between said outer coils, so as to create a uniform radial magnetic field.