Ring-cusp ion thruster with shell anode
AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration
InventorsJames S. Sovey, Vincent K. Rawlin, Robert F. Roman
Life of this patent
Estimating the term…
Abstract
An improved ion thruster (10) for low specific impulse operation in the 1500 sec to 6000 sec range has a multicusp boundary field (48) provided by high strength magnets (30-38) on an iron anode shell (14) which lengthens the paths of electrons from a hollow cathode assembly (20). A downstream anode pole piece in the form of an iron ring (40) supports a ring of magnets (44) to provide a more uniform beam profile. A cylindrical cathode magnet (46) can be moved selectively in an axial direction along a feed tube (22) to produce the desired magnetic field at the cathode tip (24).
Claims14
An improved ion thruster for low specific impulse operation in the 1500 sec to 6,000 sec range comprising
- a tubular anode shell forming a chamber for containing an ionizable propellant,
- a source of high velocity electrons within said chamber for bombarding said propellant to form ions,
- a high perveance optical system for extracting and accelerating ions from said chamber mounted on said anode shell at the downstream end of said chamber, said thruster having a back plate at anode potential mounted on the forward end of said anode shell thereby closing said chamber,
- a plurality of rings of magnets mounted on the inner surface of said tubular shell, and
- a plurality of rings of magnets mounted on the inner surface of said back plate to form with the magnets on the tubular shell a strong downstream ion flux to minimize ion losses to the side and upstream walls of said chamber.
An ion thruster as claimed in claim 6 wherein the anode 15 shell is iron.
An electron bombardment ion thruster comprising
- a housing forming the peripheral wall of discharge chamber for containing an ionizable propellant,
- means for maintaining the surfaces of said peripheral wall of said discharge chamber at anode potential to reduce ion sputter etching of the side and upstream portions thereof,
- a source of propellant in communication with said discharge chamber,
- a cathode for emitting high velocity electrons to said peripheral wall for bombarding said propellant to form ions,
- ion optical means for extracting and accelerating ions from said discharge chamber,
- a plurality of high strength magnets mounted on said housing in said chamber to form a multicusp boundary field,
- a downstream anode pole piece adjacent to said ion optics means for providing a uniform ion beam profile, and
- a magnet mounted on said cathode to couple the magnetic field in the region thereof to said high strength magnets.
Dependencies are inferred from the claim text.