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Development of ITER-relevant 1MeV negative ion beams with Multi-Aperture Multi-Grid accelerator
https://repo.qst.go.jp/records/67142
https://repo.qst.go.jp/records/671422bb83856-9aa9-40ae-9608-aeaf57489163
| Item type | 会議発表用資料 / Presentation(1) | |||||
|---|---|---|---|---|---|---|
| 公開日 | 2019-02-07 | |||||
| タイトル | ||||||
| タイトル | Development of ITER-relevant 1MeV negative ion beams with Multi-Aperture Multi-Grid accelerator | |||||
| 言語 | ||||||
| 言語 | eng | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_c94f | |||||
| 資源タイプ | conference object | |||||
| アクセス権 | ||||||
| アクセス権 | metadata only access | |||||
| アクセス権URI | http://purl.org/coar/access_right/c_14cb | |||||
| 著者 |
平塚, 淳一
× 平塚, 淳一× 小島, 有志× 柏木, 美恵子× 梅田, 尚孝× 市川, 雅浩× 錦織, 良× 渡邊, 和弘× 戸張, 博之× 平塚 淳一× 小島 有志× 柏木 美恵子× 梅田 尚孝× 市川 雅浩× 錦織 良× 渡邊 和弘× 戸張 博之 |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | ITER neutral beam injector (NBI) is required to produce 1 MeV 16.5 MW neutral beams for 3600 seconds by a neutralization of 1 MeV, 200 A/m2 deuterium negative ion beams. In order to realize such high-current density beams, a prototype accelerator with multi-aperture multi-grid concept is being developed. Up to now, 1 MeV, 200 A/m2 hydrogen negative ion beam acceleration for 60 seconds has been achieved. As a next target of R&Ds, the accelerator is being modified to accelerate 1 MeV, 280 A/m2 hydrogen negative ion beams, which have the same space charge effect as in the deuterium negative ion beams of 1 MeV, 200 A/m2. According to the Child-Langmuir law, higher electric field in the accelerator with the shorter gap length of 85-88 mm is necessary to tune the beam optics of 1 MeV, 280 A/m2. However, because the shortening of the gap length is the trade-off between the beam optics and the voltage holding capability, available gap length at 1 MV and available current density at the gap length have been investigated in the modified accelerator. As for the acceleration voltage, in order to achieve 1 MV at reduced gap lengths from 109 to 85-88 mm, the surface area of the acceleration grid has been optimized to sustain high voltage in vacuum even with the shorter gap length by taking the empirical scaling of the surface area effect on the voltage holding capability into account. As the result, 1 MV at the gap length of 88 mm without beam acceleration has been achieved as designed, which requires 40 hours conditioning as well as the previous accelerators. As for the beam optics, experiments of beam accelerations at the gap length of 88 mm is going on. As a preliminary result, the available current density has been increased, where 1 MeV 280 A/m2 is foreseen. Moreover, the total power load on the acceleration grids has been also reduced from 8.2 to 7.5 %. Since the gap lengths of 88 mm are same as the present design of the ITER accelerator, these results can contribute to the direct prediction of the performance of the ITER accelerator. | |||||
| 会議概要（会議名, 開催地, 会期, 主催者等） | ||||||
| 内容記述タイプ | Other | |||||
| 内容記述 | Korea-Japan Workshop on Physics and Technology of Heating and Current Drive | |||||
| 発表年月日 | ||||||
| 日付 | 2016-12-14 | |||||
| 日付タイプ | Issued | |||||
