| Autor: |
K Ikeda, H Nakano, K Tsumori, M Kisaki, K Nagaoka, M Osakabe, Y Takeiri, O Kaneko |
| Jazyk: |
angličtina |
| Rok vydání: |
2013 |
| Předmět: |
|
| Zdroj: |
New Journal of Physics, Vol 15, Iss 10, p 103026 (2013) |
| Druh dokumentu: |
article |
| ISSN: |
1367-2630 |
| DOI: |
10.1088/1367-2630/15/10/103026 |
| Popis: |
Extraction structure of negative hydrogen ions (H ^− ) (i.e. the regions where H ^− ions are effectively extracted from the plasma) was obtained using hydrogen Balmer- α (H _α ) imaging spectroscopy and cavity ring-down spectroscopy. The H ^− ion density increases after caesium (Cs) seeding through a surface conversion process on a Cs-covered plasma-grid (PG) surface. We found a reduction in the H ^− density during beam extraction after Cs conditioning, and the same signal reduction appeared in the H _α intensity caused by the reduction in the excited hydrogen ( n = 3) population, which in turn is caused by the decrease in the mutual neutralization process between positive and negative hydrogen ions. We clearly observed the reduction structure of the H _α emissions in the extraction region; the structure expands at optimal Cs conditioning. From this result, the H ^− ions, which are produced at the PG surface, release to the extraction region and widely distribute during arc discharge. We conclude that the reduction of the H ^− density is caused by the particle loss due to beam extraction from the PG apertures. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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