Systems and methods for continuously supplying negative ions using multi-pulsed plasma sources

Patent metadata

Field	Value
Publication number	US-11337296-B2
Application number	US-201816764658-A
Country	US
Kind code	B2
Filing date	Oct 24, 2018
Priority date	Nov 17, 2017
Publication date	May 17, 2022
Grant date	May 17, 2022

Abstract

The present disclosure relates to a system and method for continuously supplying negative ions using multi-pulsed plasma sources. The system includes a plurality of plasma generators each to generate plasma by applying pulsed power to the electronegative gas from a gas source; a negative ion supply unit connected to the plasma generators to receive the plasmas transferred therefrom and to continuously supply ions; and a controller connected to the plurality of plasma generators and configured to control characteristics of the pulsed powers delivered to the respective plasma generators and to adjust phase shift associated with the pulsed power envelopes. By adjusting the phase shift, the controller enables a plasma in one of the plasma generators to be in an after-glow state when a plasma in another plasma generator is in an active-glow state.

First claim

The invention claimed is:

1. A system for supplying negative ions using multi-pulsed plasma sources, the system comprising:
a plurality of plasma generators each configured to generate plasma by applying pulsed power to electronegative gas;
a negative ion supply unit connected to each of the plurality of plasma generators to receive the generated plasma therefrom; and
a controller connected to the plurality of plasma generators and configured to control characteristics of the pulsed powers supplied to the respective plasma generators, and to adjust phase shift between signals associated with pulsed power envelopes such that when one of the plasma generators is in an active-glow state, another plasma generator is switched to an after-glow state,
wherein the plurality of plasma generators generates the plasmas in an alternating manner depending on the phase shift between the signals associated with pulsed power envelopes in a manner that a decreased amount of negative ion supply from one of the plasma generators in the active-glow state to the negative ion supply unit is compensated for by an additional supply of negative ions supplied from another plasma generator in the after-glow state to the negative ion supply unit.

2. The system of claim 1 , wherein the plurality of plasma generators is configured such that, when one of the plasma generators supplies negative ion precursors and electrons generated in the active-glow state to the negative ion supply unit, another plasma generator supplies negative ions generated in the after-glow state to the negative ion supply unit.

3. The system of claim 1 , wherein the controller comprises a plurality of pulse controllers and a system controller, wherein:
the plurality of pulse controllers connected to the plasma generators, respectively, and configured to control the characteristics of the pulsed powers for switching the state of the plasma in each of the plasma generators between the active-glow state and the after-glow state; and
the system controller connected to the pulse controllers, and configured to adjust the phase shift between the signals associated with the pulsed power envelopes modulated by the pulse controllers, so as to delay a start time of the active-glow state of one of the plasma generators after an end time of the active-glow state of another plasma generator.

4. The system of claim 1 , further comprising a magnetic filter placed between each of the plasma generators and the negative ion supply unit,
wherein the magnetic filter restricts high-energy electrons, among the electrons generated from the plasma generators in the active-glow state, from entering the negative ion supply unit.

5. The system of claim 4 , wherein the magnetic filter comprises at least one permanent magnet.

6. The system of claim 4 , wherein the magnetic filter comprises at least one electromagnet, and
the electromagnet generates a magnetic field depending on an operating state of the plasma generator.

7. The system of claim 6 , wherein the electromagnet is interlinked with the signal associated with the pulsed power envelope so as to produce the magnetic field when the corresponding plasma generator is in the active-glow state.

8. The system of claim 1 , further comprising a plasma particle filter provided between the plasma generators and the negative ion supply unit,
wherein the plasma particle filter selectively transports particles generated in the plasma generators toward the negative ion supply unit depending on charge states thereof.

9. The system of claim 8 , wherein the plasma particle filter is provided with either of an electrode and a grid that produce an electric field.

10. The system of claim 1 , further comprising gas supply units connected to the plasma generators, respectively, and configured to supply the plasma generators with the electronegative gas.

11. The system of claim 10 , wherein the gas supply units comprise gas supply controllers, respectively, configured to control an amount of gas supplied to the plasma generators over time.

12. The system of claim 1 , further comprising a beam extraction system connected to the negative ion supply unit and configured to extract the negative ions.

13. A method for supplying negative ions using multi-pulsed plasma sources, the method comprising:
a negative ion generation-and-supply step of generating plasmas by applying pulsed powers to a plurality of plasma generators, respectively, and supplying the generated plasmas to a negative ion supply unit;
a continuous negative ion supply step of supplying the negative ions to the negative ion supply unit through an alternating operation of the plasma generators by adjusting phase shift between signals associated with pulsed power envelopes applied to the plurality of plasma generators, respectively; and
a negative ion extraction step of extracting the negative ions from the negative ion supply unit.

14. The method of claim 13 , wherein the negative ion generation-and-supply step comprises:
generating plasma containing the negative ions, negative ion precursors, and electrons when the plasma generator is in the power-on state;
supplying the negative ion precursors and the electrons to the negative ion supply unit;
generating first negative ions by reactions of the negative ion precursors with the electrons in the negative ion supply unit;
generating second negative ions in the plasma generator when power is turned off, by reactions between plasma species generated before the power is turned off; and
supplying the second negative ions to the negative ion supply unit.

15. The method of claim 14 , wherein the supplying of the negative ion precursors and the electrons to the negative ion supply unit comprises
producing a magnetic field by a magnetic filter installed between the negative ion supply unit and the plasma generator, in order to restrict high-energy electrons of the electrons from entering the negative ion supply unit.

16. The method of claim 13 , wherein the continuous negative ion supply step comprises:
adjusting the phase shift between the signals associated with the pulsed power envelopes applied to the plurality of plasma generators, respectively, so that the plasma generators are supplied with the pulsed powers with a predetermined phase lag to one another; and
allowing a plasma in one of the plasma generators to be in an after-glow state while a plasma in another plasma generator is in an active-glow state due to the applied pulsed power, and alternating the state of the plasma in each of the plurality of plasma generators between the active-glow state and the after-glow state, with the phase shift.

17. The method of claim 13 , wherein the negative ion extraction step comprises:
configuring a polarity of a beam extraction electrode connected to the negative ion supply unit; and
extracting the negative ions from the negative ion supply unit when the beam extraction electrode is positive, and extracting positive ions from the negative ion supply unit when the beam extraction electrode is negative.

Assignees

• Korea Atomic Energy Res

Inventors

• Huh Sungryul

Classifications

• H05H2242/20

  Power circuits · CPC title

• H01J37/3244

  Gas supply means · CPC title

• H01J27/028 Primary

  Negative ion sources · CPC title

• H01J37/32146

  Amplitude modulation, includes pulsing · CPC title

• G21B1/15

  Particle injectors for producing thermonuclear fusion reactions, e.g. pellet injectors · CPC title