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Your search keyword '"Kashiwagi, M."' showing total 6 results
Start Over Author "Kashiwagi, M." Topic hydrogen ions Topic ion sources
6 results on '"Kashiwagi, M."'

1. Experimental Validation of an Innovative Deflection Compensation Method in a multi-Beamlet Negative-Ion Accelerator.

Author

Chitarin, G., Kojima, A., Agostinetti, P., Aprile, D., Baltador, C., Hiratsuka, J., Ichikawa, M., Marconato, N., Sartori, E., Serianni, G., Veltri, P., Yoshida, M., Kashiwagi, M., Hanada, M., and Antoni, V.

Subjects
ION accelerators, ANIONS, MAGNETIC fields, HYDROGEN ions, ION sources
Abstract

An innovative magnetic configuration called ADCM (Asymmetric Deflection Compensation Magnets) has been recently proposed for the cancellation of the "criss-cross" deflection of ion trajectories in multi-beamlet negative ion accelerators. Such undesired deflection occurs due to the transverse magnetic field, which is necessary for the suppression of co-extracted electrons. In view of the application of this concept to the ITER Heating Neutral Beam Injector, the new configuration has been experimentally tested for the first time in 2016, in the framework of a research collaboration between Consorzio RFX and QST. [ABSTRACT FROM AUTHOR]

Published
2017
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2. The Effect of Transport and Extraction of Non-Uniform Surface Produced H- in Large Multi-Aperture Negative Ion Sources.

Author

Fujita, S., Yamamoto, T., Yoshida, M., Kashiwagi, M., and Hatayama, A.

Subjects
ANIONS, ION sources, HYDROGEN ions, BEAM optics, PLASMA potentials, PARTICLE beam extraction
Abstract

In order to compare the simulation and the experiments of the extracted H- beams in JT-60SA negative ion source, an analysis of H- ion transport has been conducted. It has been shown that, under the present conditions, the calculated beam profile correlates well with the experiments, and the majority of the extracted H- ions are produced at the surface of the extraction aperture. However, since those H- ions could contribute to beam halo, a careful evaluation of the beam optics, taking into account more realistic plasma potential will be needed in the future works. [ABSTRACT FROM AUTHOR]

Published
2018
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3. Numerical analysis of negative hydrogen ion beam optics by using 3D3V PIC simulation.

Author

Miyamoto, K., Nishioka, S., Hatayama, A., Mizuno, T., Hiratsuka, J., and Kashiwagi, M.

Subjects
HYDROGEN ions, ION beams, BEAM optics, ANIONS, ION sources
Abstract

The negative ion beam optics is studied quantitatively from the viewpoints of the heat loads due to the beam halo in the accelerator and the emittance of the negative ion beam by using the 3D3V PIC model combined with a Monte Carlo calculation, in which negative ion beam from plasma meniscus formation to the beam acceleration is modeled. As for the heat loads of the A2G and the GRG, the simulation result almost agrees with the experimental result. The simulation result indicates that the secondary electrons from the extractor also contribute to the heat load of the A1G. Moreover, the normalized rms emittance of the negative ion beam after the exit of the GRG are estimated to be around 0.25π mm mrad, which are compatible with the typical values of the negative ion sources. [ABSTRACT FROM AUTHOR]

Published
2018
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4. Workshop on performance variations in H- ion sources 2012: PV H-12.

Author

Stockli, M. P., Faircloth, D., Kraus, W., Ando, A., Bollinger, D. S., Briefi, S., Fantz, U., Friedl, R., Kashiwagi, M., King, D., Koivisto, H., Han, B. X., Lettry, J., Takeiri, Y., Tarvainen, O., Tsumori, K., Welton, R. F., and Wimmer, Ch.

Subjects
HYDROGEN ions, ION sources, HYDROGEN production, PERFORMANCE evaluation, WORKSHOPS (Facilities)
Abstract

This paper briefly summarizes a workshop held in Jyvaskyla the day after NIBS'12. The half-day workshop aimed at globally capturing the issue of performance variations in H- sources. There was a focus on production facilities and facilities that work under production-like conditions, because there are often high expectations to be met. [ABSTRACT FROM AUTHOR]

Published
2013
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5. Acceleration of MeV-class energy, high-current-density H--ion beams for ITER neutral beam system.

Author

Taniguchi, M., Inoue, T., Kashiwagi, M., Watanabe, K., Hanada, M., Seki, T., Dairaku, M., and Sakamoto, K.

Subjects
ION bombardment, NEUTRAL beams, RESEARCH institutes, ION sources, ANIONS, HYDROGEN ions, COLLISIONS (Nuclear physics), ELECTRIC insulators & insulation, ENERGY dissipation
Abstract

For the ITER neutral beam system, reasearch and development of a vacuum-insulated MeV accelerator has been carried out at Japan Atomic Energy Research Institute. After a successful 1 MV insulation in vacuum for more than 2 h, H--ion-beam acceleration test is in progress to fulfill the ITER requirement of the current density of 200 A/m2 at 1 MeV, with good beam optics quality of <7 mrad divergence. For such a high-current-density H--ion-beam acceleration, the Kamaboko negative-ion source was operated at high input power, with increased filament number and magnetic filter strength. The optimum perveance was investigated by scanning the extraction and acceleration voltages, together with the beam divergence measurement. As a consequence, H--ion beams of 146 A/m2 (total ion-beam current: 206 mA) were obtained at 836 keV, of which power density is in the “ITER relevant” level. Such high-power-density beams with a divergence as low as 5 mrad were obtained at the optimum perveance corresponding to that of the ITER (200 A/m2 at 1 MeV). [ABSTRACT FROM AUTHOR]

Published
2006
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6. Improvement of beam uniformity by magnetic filter optimization in a Cs-seeded large negative-ion source.

Author

Hanada, M., Seki, T., Takado, N., Inoue, T., Tobari, H., Mizuno, T., Hatayama, A., Dairaku, M., Kashiwagi, M., Sakamoto, K., Taniguchi, M., and Watanabe, K.

Subjects
ION sources, ANIONS, CESIUM, PLASMA gases, ELECTRONS, MAGNETS, HYDROGEN ions, PROTONS, MAGNETIC fields
Abstract

The influence of magnetic filter configuration on the beam uniformity was examined to improve beam uniformity in a large Cs-seeded negative-ion source. By reducing the filter strength of the transverse magnetic field used in a typical negative-ion source, the beam uniformity was largely improved with the improvement of the plasma uniformity while the beam intensity was kept to be nearly constant. However, the coextracted electron current greatly increased. To suppress the coextracted electron current, a tent-shaped magnetic filter was applied together with modifications in the cusp magnets to form a typical multicusp positive-ion source arrangement. The uniformity in longitudinal beam profile was improved with the deviation of local beam intensity within 16% that was nearly equal to the deviation obtained at 50 G cm of the transverse filter strength. In the meantime, the coextracted electron current was kept to be the same as the H- ion current. The present result suggests that the uniformity of H- ion-beam profile is affected by the uniformity of atoms or protons in the source plasma, which are the primary species of negative ions under Cs-seeded surface production. [ABSTRACT FROM AUTHOR]

Published
2006
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