Experimental study on spatial uniformity of H− ion beam in a large negative ion source

Hanada, M.; Seki, T.; Takado, N.; Inoue, Takashi; Morishita, T.; Mizuno, T.; Hatayama, A.; Imai, T.; Kashiwagi, M.; Sakamoto, K.; Takeuchi, Masaki; Watanabe, K.

doi:10.1016/j.fusengdes.2005.06.259

Cited by 10 publications

(13 citation statements)

References 8 publications

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“…The data were calculated using Eq. 4,20,21 Figure 4͑b͒ shows the electron temperature and density of thermal electrons. Figure 4͑a͒ shows the data on electrons in the high-energy tail estimated from the two-temperature fit.…”

Section: A H 0 Atom Production Profilementioning

confidence: 99%

Numerical analysis of the production profile of H atoms and subsequent H− ions in large negative ion sources

Takado

Tobari

Inoue

et al. 2008

Journal of Applied Physics

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Articles you may be interested inModeling of neutrals in the Linac4 H− ion source plasma: Hydrogen atom production density profile and Hα intensity by collisional radiative modela) Rev. Sci. Instrum. 85, 02B118 (2014); 10.1063/1.4833016 Role of positive ions on the surface production of negative ions in a fusion plasma reactor type negative ion source-Insights from a three dimensional particle-in-cell Monte Carlo collisions model Phys. Plasmas 20, 113511 (2013); 10.1063/1.4834475 Effect of non-uniform electron energy distribution function on plasma production in large arc driven negative ion sourcea) Rev. Sci. Instrum. 83, 02A719 (2012); 10.1063/1.3673485 Effect of energy relaxation of H 0 atoms at the wall on the production profile of H − ions in large negative ion sourcesa) Rev. Sci. Instrum. 79, 02A503 (2008); 10.1063/1.2802583 Monte Carlo simulation of negative ion production in the negative hydrogen ion source Rev. Sci. Instrum. 71, 883 (2000)The production and transport processes of H 0 atoms are numerically simulated using a three-dimensional Monte Carlo transport code. The code is applied to the large JAEA 10 ampere negative ion source under the Cs-seeded condition to obtain a spatial distribution of surface-produced H − ions. In this analysis, the amount of H 0 atoms produced through dissociation processes of H 2 molecules is calculated from the electron temperature and density obtained by Langmuir probe measurements. The high-energy tail of electrons, which greatly affects H 0 atom production, is taken into account by fitting a single-probe characteristic as a two-temperature Maxwellian distribution. In the H 0 atom transport process, the energy relaxation of the H 0 atoms, which affects the surface H − ion production rate, is taken into account. The result indicates that the surface H − ion production is enhanced near the high-electron-temperature region where H 0 atom production is localized.

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Section: A H 0 Atom Production Profilementioning

confidence: 99%

Numerical analysis of the production profile of H atoms and subsequent H− ions in large negative ion sources

Takado

Tobari

Inoue

et al. 2008

Journal of Applied Physics

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“…1, showing the conventional configuration with "external magnetic filter". This is confirmed by electron temperature measurement by Langmuir probes, showing strong gradient of electron temperature in the driver region [13,14]. • Under Cesium seeded condition, negative ion production is enhanced in the extraction region, and its production rate is dependent on the local plasma parameters, such as the plasma density, and the electron temperature.…”

Section: Uniform Negative Ion Production In a Large Sourcementioning

confidence: 57%

Development of beam source and bushing for ITER NB system

Inoue

Hanada

Kashiwagi

et al. 2007

Fusion Engineering and Design

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“…In the existing negative ion sources, a transverse magnetic field, called a "magnetic filter," is applied and the negative ions are produced in low temperature plasmas diffused through the magnetic filter. A previous experiment in the JAEA 10-ampere ion source [7] revealed that the negative ion destruction was enhanced in the high-electron temperature region localized in the ion source. Namely, a drastic reduction of local beam intensity has been observed in the region where local electron temperature is relatively high in a conventional "pure volume" condition.…”

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confidence: 91%

“…In the original configuration of the 10-ampere source as shown in Fig. 1, the longitudinal distributions of plasma parameters (electron temperature T e and ion saturation current density J is at Z = 14 mm) show a steep gradient with higher T e and J is in the top region [7] (See Figs. 2 (a) and (b)).…”

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confidence: 99%

Negative Ion Production in High Electron Temperature Plasmas

Tobari

Seki

Takado

et al. 2007

Plasma and Fusion Research

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In our recent experiment, it was found that intense negative ion beams could be extracted from high-density and high-electron temperature plasmas under a Cesium seeded condition. This indicates that such plasmas contribute to the surface production of negative ions, and that the negative ion production exceeds the destruction process via electron detachment. Thus, it has been suggested that highly ionized and dissociated plasmas are suitable for the surface production of negative ions. This paper reports the results of specific experiments to confirm the negative ion production in plasmas with high-electron temperature. In these experiments, high electron temperature plasmas were produced by (1) placing filaments (acting as cathodes) near the extraction area, and (2) reducing the magnetic filter strength, both to allow fast electrons access to the beam extraction area. The results support the production of high-density H − ions even in plasmas with high-electron temperature. Also included is a discussion on the surface production mechanism of negative ions under a Cs-seeded condition.

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Experimental study on spatial uniformity of H− ion beam in a large negative ion source

Cited by 10 publications

References 8 publications

Numerical analysis of the production profile of H atoms and subsequent H− ions in large negative ion sources

Numerical analysis of the production profile of H atoms and subsequent H− ions in large negative ion sources

Development of beam source and bushing for ITER NB system

Negative Ion Production in High Electron Temperature Plasmas

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