Cesium-seeded experiments on the 1/3-scaled H− ion source for large helical device

Andõ, Akira; Tsumori, K.; Takeiri, Y.; Kaneko, O.; Oka, Y.; Okuyama, T.; Kojima, Hiroaki; Yamashita, Yasuo; Akiyama, R.; Kawamoto, T.; Mineo, K.; Kurata, T.; Kuroda, T.

doi:10.1063/1.44796

Cited by 10 publications

(3 citation statements)

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“…In addition, for clean metallic surfaces (tungsten) the reflected atomic hydrogen particle energy is numerically evaluated to be around 65% of the impact energy at normal incidence and for = E 1 eV k [51]. Lastly, it has been reported in the experiments that the extracted negative ion current increases only slightly with cesium when the PG is water-cooled [52] while a PG heated to a temperature of~ 100 C-250 • C induces a significant increase of the negative ion current, by a factor~-4 5 in the experimental conditions of [5,52] (the other walls of the ion-source were water-cooled). In the model, we consequently assume that negative ions may only be produced on the cesiated PG surface.…”

Section: Negative Ionsmentioning

confidence: 99%

Modeling of plasma transport and negative ion extraction in a magnetized radio-frequency plasma source

et al. 2017

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Negative ion sources for fusion are high densities plasma sources in large discharge volumes. There are many challenges in the modeling of these sources, due to numerical constraints associated with the high plasma density, to the coupling between plasma and neutral transport and chemistry, the presence of a magnetic filter, and the extraction of negative ions. In this paper we present recent results concerning these different aspects. Emphasis is put on the modeling approach and on the methods and approximations. The models are not fully predictive and not complete as would be engineering codes but they are used to identify the basic principles and to better understand the physics of the negative ion sources. e . (ii) A low electron temperature in the OPEN ACCESS RECEIVED

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Section: Negative Ionsmentioning

confidence: 99%

Modeling of plasma transport and negative ion extraction in a magnetized radio-frequency plasma source

et al. 2017

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“…[1][2][3][4][5][6] The neutral beams with the power of several megawatts provide in those injectors. [1][2][3][4][5][6] The neutral beams with the power of several megawatts provide in those injectors.…”

Section: Introductionmentioning

confidence: 99%

Beamlet characteristics in the accelerator with multislot grounded grid

Tsumori

Osakabe

Takeiri

et al. 2010

Review of Scientific Instruments

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Characteristics of multibeamlets are investigated by means of beamlet monitoring technique. The beamlets are extracted from an accelerator with multislot grounded grid and the profiles are observed as infrared images of temperature distributions on a cold isostatic pressed graphite plate exposed by H-beamlets. The optimal horizontal and vertical divergence angles of single beamlet are estimated at 4.1 and 6.1 mrad, respectively.

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“…The research and development of negative-ion sources have been extensively performed in connection with neutral beam injection heating for fusionoriented plasmas. [6][7][8][9] Cesium is a solid at room temperature but exists as a gas or ion in an ion source. During the operation of the ion source, the recycling of cesium with a phase transition occurs within the ion source.…”

Section: Introductionmentioning

confidence: 99%

Production of negative hydrogen ions on metal grids

et al. 2015

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Negative hydrogen ions are produced on a nickel grid with positive-ion irradiation. In order to investigate the production mechanism, a copper grid without the chemisorption of hydrogen atoms and positive helium ions without negative ionization are used for comparison. Positive hydrogen ions reflected on the metal surface obtain two electrons from the surface and become negatively ionized. It is found that the production yield of negative ions by desorption ionization of chemisorbed hydrogen atoms seems to be small, and the production is a minor mechanism. V C 2015 AIP Publishing LLC. [http://dx.

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Cesium-seeded experiments on the 1/3-scaled H− ion source for large helical device

Cited by 10 publications

References 0 publications

Modeling of plasma transport and negative ion extraction in a magnetized radio-frequency plasma source

Modeling of plasma transport and negative ion extraction in a magnetized radio-frequency plasma source

Beamlet characteristics in the accelerator with multislot grounded grid

Production of negative hydrogen ions on metal grids

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