Patent US4239594A successfully refreshed from Google Patents.
US4239594A
Expired / Lapsed
US
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Control of impurities in toroidal plasma devices
Assignee: United States Department of Energy
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Filing: 1975-08-29
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Granted: 1980-12-16
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Expires: 1995-08-29
Abstract
Abstract A method and apparatus for plasma impurity control in closed flux plasma systems such as Tokamak reactors is disclosed. Local axisymmetrical injection of hydrogen gas is employed to reverse the normally inward flow of impurities into the plasma.
Inventors
- 👤 Tihiro Ohkawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 22:39
CPC Classifications
G; G21; G21B; G21B1/00; G21B1/05; G21B1/057; Y; Y02; Y02E; Y02E30/00; Y02E30/10
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
201 words
Toroidal plasma confinement apparatus having a positive ion toroidal magnetic drift in a direction along the major toroidal axis including means for the control of impurity flow into a hydrogen plasma comprising means for providing a toroidal magnetic field in which the plasma is embedded, means for providing a toroidal current in the plasma and for generating a poloidal magnetic field in which the plasma is embedded, means for providing an axisymmetric source of hydrogen in a minor azimuthal zone adjacent the plasma and displaced from the plasma in a direction along the major toroidal axis opposite the direction of positive ion toroidal drift, and an axisymmetric particle sink in a minor azimuthal zone adjacent the plasma and displaced from the plasma along the major toroidal axis in the direction of positive ion toroidal drift, the source strength of said axisymmetric source of hydrogen being at least ##EQU13## particles per second for reversal of impurity flow such that said source replenishes protons lost from the plasma by the positive ion toroidal drift to eliminate circulation flow of impurity ions along the flux lines of the toroidal and poloidal magnetic fields which otherwise would result in net impurity influx into the plasma.
Claim 2
Dependent Claim
201 words
Toroidal plasma confinement apparatus having a positive ion toroidal magnetic drift in a direction along the major toroidal axis including means for the control of impurity flow into a hydrogen plasma comprising means for providing a toroidal magnetic field in which the plasma is embedded, means for providing a toroidal current in the plasma and for generating a poloidal magnetic field in which the plasma is embedded, means for providing an axisymmetric source of hydrogen in a minor azimuthal zone adjacent the plasma and displaced from the plasma in a direction along the major toroidal axis opposite the direction of positive ion toroidal drift, and an axisymmetric particle sink in a minor azimuthal zone adjacent the plasma and displaced from the plasma along the major toroidal axis in the direction of positive ion toroidal drift, the source strength of said axisymmetric source of hydrogen being at least ##EQU13## particles per second for reversal of impurity flow such that said source replenishes protons lost from the plasma by the positive ion toroidal drift to eliminate circulation flow of impurity ions along the flux lines of the toroidal and poloidal magnetic fields which otherwise would result in net impurity influx into the plasma.
Claim 3
Independent Claim
159 words
A method for control of impurity flow into a toroidally confined plasma, comprising the steps of providing an axisymmetric source of hydrogen in a zone adjacent the plasma within the toroidal and poloidal magnetic field confining the plasma and displaced from the plasma in a direction along the major toroidal axis opposite the direction of positive ion toroidal drift, introducing hydrogen to said zone at a hydrogen source strength rate of at least ##EQU14## particles per second and ionizing said hydrogen through interaction with said plasma to replace protons lost by toroidal magnetic drift to eliminate circulation flow of impurity ions along flux lines of the toroidal and magnetic field which otherwise would result in net impurity influx into the plasma, neutralizing plasma particles in a zone adjacent the plasma and displaced from the plasma along the major toroidal axis in the direction of positive ion toroidal drift, and evacuating the plasma zone adjacent the zone of particle neutralization.
Claim 4
Independent Claim
159 words
A method for control of impurity flow into a toroidally confined plasma, comprising the steps of providing an axisymmetric source of hydrogen in a zone adjacent the plasma within the toroidal and poloidal magnetic field confining the plasma and displaced from the plasma in a direction along the major toroidal axis opposite the direction of positive ion toroidal drift, introducing hydrogen to said zone at a hydrogen source strength rate of at least ##EQU14## particles per second and ionizing said hydrogen through interaction with said plasma to replace protons lost by toroidal magnetic drift to eliminate circulation flow of impurity ions along flux lines of the toroidal and magnetic field which otherwise would result in net impurity influx into the plasma, neutralizing plasma particles in a zone adjacent the plasma and displaced from the plasma along the major toroidal axis in the direction of positive ion toroidal drift, and evacuating the plasma zone adjacent the zone of particle neutralization.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-12-16 | 1984-06-16 | 1984-12-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-12-16 | 1988-06-16 | 1988-12-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-12-16 | 1992-06-16 | 1992-12-16 | $7700.00 | Window Closed / Lapsed |