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US 2019/0168895 A1Published application
Low-power hall thruster with an internally mounted low-current hollow cathode
AssigneeCalifornia Institute of Technology
InventorsRyan W CONVERSANO, Dan M GOEBEL, Ira KATZ, Richard R HOFER
Life of this patent
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Abstract
A low-power Hall thruster gains significantly improved efficiency by a combination of features, including a single piece, h-shaped magnetic screen which enables a more efficient internal volume utilization as well as optimal magnetic shielding; an internally mounted cathode with varying diameter further decreases the footprint of the thruster; an anode with multiple baffles connected by axially oriented holes generates a highly azimuthally uniform propellant flow.
Claims19
A Hall thruster comprising:
- a center axis oriented from an upstream section of the Hall thruster, the upstream section housing a back pole for a magnetic circuit and a supply line for a gas propellant, to a downstream section concentric with an azimuthally-symmetrical discharge chamber;
- and
- a single-piece azimuthally-symmetrical magnetic screen,
- wherein:
- the azimuthally-symmetrical discharge chamber has an annular shape,
- the single-piece azimuthally-symmetrical magnetic screen has an h-shape cross section, the h-shape cross section comprising a first prong at an upstream end and two prongs at a downstream end,
- the single-piece azimuthally-symmetrical magnetic screen comprises a first hollow cylinder physically contacting the back pole at a single circular point of contact,
- the single-piece azimuthally-symmetrical magnetic screen comprises a second hollow cylinder and a third hollow cylinder, the second hollow cylinder being concentric to the third hollow cylinder, and
- the azimuthally-symmetrical discharge chamber comprises a radially-outward wall and a radially-inward wall,
- the second hollow cylinder of the single-piece azimuthally-symmetrical magnetic screen encircles the radially-inward wall of the azimuthally-symmetrical discharge chamber, and
- the third hollow cylinder of the single-piece azimuthally-symmetrical magnetic screen encircles the radially-outward wall of the azimuthally-symmetrical discharge chamber, thereby forming a magnetic field protecting the radially-outward wall and the radially-inward wall of the azimuthally-symmetrical discharge chamber from erosion due to ion bombardment.
8 more elements
A Hall thruster comprising:
- a center axis oriented from an upstream section of the Hall thruster, the upstream section housing a back pole for a magnetic circuit and a supply line for a gas propellant, to a downstream section concentric with an azimuthally-symmetrical discharge chamber;
- and
- an internally-mounted cathode along the center axis, the internally-mounted cathode having a variable diameter,
- wherein:
- the internally-mounted cathode comprises an upstream section and a downstream section, and
- the upstream section is axially longer than the downstream section.
3 more elements
A Hall thruster comprising:
- a center axis oriented from an upstream section of the Hall thruster, the upstream section housing a back pole for a magnetic circuit and a supply line for a gas propellant, to a downstream section concentric with an azimuthally-symmetrical discharge chamber;
- and
- an azimuthally-symmetrical anode within the azimuthally-symmetrical discharge chamber,
- wherein:
- the azimuthally-symmetrical anode comprises a plurality of baffles configured to increase azimuthal flow uniformity for the gas propellant,
- the plurality of baffles comprises at least:
- a first baffle comprising a first plurality of holes connecting the first baffle to the supply line;
- a second baffle adjacent to the first baffle and connected to the first baffle through a second plurality of holes;
- and
- a third baffle adjacent to the second baffle and connected to the second baffle through a third plurality of circular holes,
- the first baffle is upstream of the second baffle,
- the second baffle is upstream of the third baffle,
- the first, second and third baffles are azimuthally-symmetrical,
- the third baffle comprises a radially-inward surface and a radially-outward surface, and
- the third baffle comprises a fourth plurality of holes on the radially-inward and radially-outward surfaces.
12 more elements
Dependencies are inferred from the claim text.