IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0834373
(2001-04-13)
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발명자
/ 주소 |
- Fisch, Nathaniel J.
- Raitses, Yevgeny
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출원인 / 주소 |
- General Plasma Technologies LLC
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인용정보 |
피인용 횟수 :
13 인용 특허 :
5 |
초록
▼
An apparatus and method for thrusting plasma, utilizing a Hall thruster with segmented electrodes along the channel, which make the acceleration region as localized as possible. Also disclosed are methods of arranging the electrodes so as to minimize erosion and arcing. Also disclosed are methods of
An apparatus and method for thrusting plasma, utilizing a Hall thruster with segmented electrodes along the channel, which make the acceleration region as localized as possible. Also disclosed are methods of arranging the electrodes so as to minimize erosion and arcing. Also disclosed are methods of arranging the electrodes so as to produce a substantial reduction in plume divergence. The use of electrodes made of emissive material will reduce the radial potential drop within the channel, further decreasing the plume divergence. Also disclosed is a method of arranging and powering these electrodes so as to provide variable mode operation.
대표청구항
▼
1. A Hall thruster with closed electron drift, with a substantially axial electric field applied across a coaxial channel, with substantially radial magnetic fields applied across said channel, such that ions are accelerated and can flow axially across said magnetic field, but such that electrons dr
1. A Hall thruster with closed electron drift, with a substantially axial electric field applied across a coaxial channel, with substantially radial magnetic fields applied across said channel, such that ions are accelerated and can flow axially across said magnetic field, but such that electrons drift substantially in the azimuthal direction, comprising of:an annular channel, said channel formed between an outer wall that forms an outer cylindrical structure and an inner wall that forms an inner cylindrical structure, with said inner and outer walls made of an insulator material; anda distributor of propellant gas, such that said gas is ionized in channel and then said ions are accelerated by said electric field; andan anode, near the point of entry of the propellant gas into the channel; anda cathode-neutralizer, located outside said channel, that both neutralizes said ion flow and establishes total accelerating voltage of said ions; anda magnetic circuit that produces said substantially radial magnetic field; andelectrode segments of conducting material, placed along said channel, separated electrically by spacers of dielectric material; andan electric circuit holding said electrode segments at specific potentials, so as to control the axial potential within the thruster channel. 2. An apparatus according to claim 1 such that the segmented electrodes along said coaxial channel comprise rings of conducting material on the outer channel radii only. 3. An apparatus according to claim 1 such that the segmented electrodes along said coaxial channel comprise rings of conducting material on the inner channel radii only. 4. An apparatus according to claim 1 such that said rings of conducting material are on the inner and outer channel radii, with said rings on inner and outer radii arranged in pairs, with each said pair intersecting substantially the same line of magnetic force. 5. An apparatus according to claim 1 such that said rings of conducting material are made of emissive material. 6. An apparatus according to claim 1 such that said rings of conducting material are made of substantially non-emissive material. 7. An apparatus according to claim 1 such that said rings of conducting material are on the inner and outer channel radii, with said rings on inner and outer radii arranged in a staggered design, such that electrodes placed on either said inner channel wall or said outer channel wall are followed by electrodes placed on the opposite wall, so as establish an axial potential with maximum physical distance between material electrode segments. 8. An apparatus according to claim 7 such that one segmented electrode ring of conducting material is placed on the anode-side of the magnetic field maximum; andone segmented electrode ring is placed between said anode-side segmented electrode and the thruster exit; andsuch that said anode-side segmented electrode is biased negative with respect to the anode. 9. An apparatus according to claim 7 such that said rings of conducting material are made of emissive material. 10. An apparatus according to claim 1 such that one set of electrodes establishes a localized potential drop in the acceleration region; andsuch that one segmented electrode ring of conducting emissive material is placed on the anode-side of the magnetic field maximum; andsuch that said anode-side segmented electrode is biased negative with respect to the anode; andsuch that said anode-side emissive electrode emits electrons sufficient for ionization of the propellant gas. 11. An apparatus according to claim 1 such that said rings of conducting material are made of emissive material, andsuch that one set of electrodes establishes a localized potential drop in the acceleration region; andsuch that one segmented electrode ring of conducting emissive material is placed on the cathode-side of the magnetic field maximum; andsuch that said cathode-side emissive electrode emits electrons sufficient for neutralization of the i on stream. 12. An apparatus according to claim 1 such that said segmented electrode annular rings of conducting material are positioned in the region along said thruster channel so as to establish a large axial potential drop where the applied radial magnetic field is substantially in the radial direction across the full channel, so as to optimally limit the ion plume divergence. 13. An apparatus according to claim 1 such that said segmented electrode annular rings of conducting material are positioned in the region along said thruster channel so as to establish a large axial potential drop where the applied radial magnetic field is substantially in the radial direction, but also concave outwards towards the thruster exit, so as to produce a focusing effect on the accelerated ions. 14. An apparatus according to claim 1 such that said electrodes are annular rings of conducting material positioned in the region along said thruster channel so as to establish a large axial potential drop where the applied radial magnetic field is substantially purely in the radial direction across the full channel; andsuch that the segmented electrode ring closest to the anode juts out into said thruster channel, thereby to constrict the plasma flow within the channel, so as to provide greater ionization. 15. An apparatus according to claim 5 such that said emissive electrodes are made of high-temperature low-sputtering low work-function material, such as LaB6, dispenser tungsten, or barium oxide. 16. An apparatus according to claim 6 such that said non-emissive electrodes are made of low-sputtering material, such as graphite or graphite modifications such as carbon-carbon fibers, tungsten, or molybdenum. 17. An apparatus according to claim 1 such that said electric circuit includes switching circuitry capable of providing variable operation. 18. An apparatus according to claim 1 such that said propellant gas is xenon and such that said total accelerating voltage potential is approximately 300 volts. 19. A Hall thruster with closed electron drift, with a substantially axial electric field applied across a coaxial channel, with substantially radial magnetic fields applied across said channel, such that ions are accelerated and can flow axially across said magnetic field, but such that electrons drift substantially in the azimuthal direction, comprising of:an annular channel, said channel formed between an outer wall that forms an outer cylindrical structure and an inner wall that forms an inner cylindrical structure, with said inner and outer walls made of an insulator material; anda distributor of propellant gas, such that said gas is ionized in channel and then said ions are accelerated by said electric field; andan anode, near the point of entry of the propellant gas into the channel; anda magnetic circuit that produces said substantially radial magnetic field; anda pair of electrode segments of emissive conducting material, placed along said channel; andsuch that said rings of electrodes establish a localized potential drop in the acceleration region; andsuch that said cathode-side emissive electrode emits electrons sufficient for neutralization of the accelerated ions, thereby eliminating the need for a separate cathode-neutralizer; andan electric circuit holding said electrode segments at specific potentials, so as to control the axial potential within the thruster channel. 20. An apparatus according to claim 19,such that a potential drop is established between the anode-side emissive electrode and the anode; andsuch that said anode-side emissive electrode emits electrons sufficient for ionization of the propellant gas.
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