Plasma Production by Molecular Ion Injection into a Magnetic Mirror Supplemented with a Radio Frequency Electric Field

Akimune, Hideo

doi:10.1063/1.1693314

“…In elaborating the device, it was endeavored, in particular : (i) to produce a plasma possessing a density of the order of 10 11 rv 10 12 ions/cm 3 , in steady state, (ii) to use a hollow electron beam with an annular tungsten filament to ensure a nearly homogeneous distribution of ion density in the vicinity of the ion extraction aperture, (iii) to obtain an abundance of hot electrons in the ion extraction region, (iv) to assure extended useful life time for the electron emitter, (v) to provide for the possibility of scaling up.…”

Section: Ll Designmentioning

confidence: 99%

Intense and Small Emittance Hydrogen Ion Beam Formation by BPD Ion Source

Nunogaki

¹

,

Akimune

²

,

Suita

³

1976

J. Nucl. Sci. Technol.

1

0

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An ion source of original concept, named "BPD Ion Source" is described, in which the source plasma is produced by an electron beam-plasma discharge. A hydrogen ion beam of 120 rnA can be continuously extracted from the plasma in the direction of the electron beam at an extraction voltage of 30 kV through a single circular aperture of 8 mm dia. located at the bottom of the discharge chamber. The current density has reached 239 mA/cm 2 • The hot electrons contained in the source plasma facilitate the extraction of this intense ion beam. The normalized emittance of this source was observed to be 9.4 x 10-7 m-rad with 100 rnA beam extraction. The abundance ratio of the beam ion species and other characteristics are described and a discussion is presented on the possibility of scaling up for purposes of practical application.

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Intense and Small Emittance Hydrogen Ion Beam Formation by BPD Ion Source

Nunogaki

¹

,

Akimune

²

,

Suita

³

1976

Journal of Nuclear Science and Technology

2

0

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An ion source of original concept, named "BPD Ion Source" is described, in which the source plasma is produced by an electron beam-plasma discharge. A hydrogen ion beam of 120 rnA can be continuously extracted from the plasma in the direction of the electron beam at an extraction voltage of 30 kV through a single circular aperture of 8 mm dia. located at the bottom of the discharge chamber. The current density has reached 239 mA/cm 2 • The hot electrons contained in the source plasma facilitate the extraction of this intense ion beam. The normalized emittance of this source was observed to be 9.4 x 10-7 m-rad with 100 rnA beam extraction. The abundance ratio of the beam ion species and other characteristics are described and a discussion is presented on the possibility of scaling up for purposes of practical application.

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Two-Stage-Discharge Ion Source

Nunogaki

¹

,

Naito

²

,

Akimune

³

1979

Journal of Nuclear Science and Technology

2

0

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A two-stage-discharge ion source is proposed, in which a source plasma is produced through two stages of plasma production : first, an electron beam-plasma-discharge ; second, a kind of hollow-cathode a r c discharge. T h e first stage discharge produces a plasma containing abundant hot electrons. T h e plasma is then fed into the second stage, where -at a fairly low hydrogen gas pressure ( P < 4 m Torr)-a stable discharge is maintained by means of a cylinder electrode. T h i s cylinder electrode, connected to its own d c power supply, effectively serves to increase t h e ion density and to flatten its radial distribution. T h e source plasma generated by t h e foregoing two-stage-discharge permits the extraction of a high current ion beam of increased beam perveance. When a cylinder electrode of 6.5 cm diameter w a s used, the plasma ion density measured in the circular area of 4 cm diameter in front of the ion extraction aperture array w a s of a n order of 1012cm-3 with a radial density fluctuation within +0.1%.A description is given of this source, together with an analysis of the function of hot electrons on ion beam formation. A preliminary experiment on ion beam formation from this source plasma succeeded in obtaining a continuous hydrogen ion beam of 1.17 A a t an extraction voltage of 30 kV, with use of multiaperture electrodes provided with seven apertures each of 9 mm diameter. T h e ion beam had a current density of 260mA.DC/cm2. KEYWORDS: thermonuclear fusion experiment, "two-stage-discharge ion source", hydrogen ion beam, cylinder electrode, combination o f fwo kinds o f dischqrge, hot electron plasma, spatial ion density profile, beam perveance, 260 rnA.DClcm2

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Plasma Production by Molecular Ion Injection into a Magnetic Mirror Supplemented with a Radio Frequency Electric Field

Abstract: Articles you may be interested inApplication of sheet shaped plasma supplemented with radio frequency plasma source for production of thin films Rev. Sci. Instrum. 71, 4483 (2000)

Cited by 6 publications

References 11 publications

Intense and Small Emittance Hydrogen Ion Beam Formation by BPD Ion Source

Intense and Small Emittance Hydrogen Ion Beam Formation by BPD Ion Source

Intense and Small Emittance Hydrogen Ion Beam Formation by BPD Ion Source

Two-Stage-Discharge Ion Source

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