Academic Journal
Ultrahigh neutral pressures in the sub-divertor of the Large Helical Device
| Title: | Ultrahigh neutral pressures in the sub-divertor of the Large Helical Device |
|---|---|
| Authors: | U. Wenzel, G. Motojima, M. Kobayashi, M. Goto, Y. Hayashi, S. Masuzaki, G. Kawamura, B. Jagielski, V. Haak |
| Source: | Nuclear Fusion, Vol 64, Iss 3, p 034002 (2024) |
| Publisher Information: | IOP Publishing, 2024. |
| Publication Year: | 2024 |
| Collection: | LCC:Nuclear and particle physics. Atomic energy. Radioactivity |
| Subject Terms: | stellarator, LHD, divertor, particle exhaust, neutral pressure, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798 |
| More Details: | In the Large Helical Device (LHD) a low temperature mode (LTM) of the helical divertor was discovered. It combines particle detachment and very large sub-divertor pressures up to 1.4 Pa. During the LTM, the electron temperature in the divertor was in the range from 0.25 to 0.42 eV so that volume recombination occurred. This result is remarkable because in the stellarators LHD and Wendelstein 7-X only low sub-divertor pressures (0.03–0.3 Pa) were expected and measured up to now due the loss of pressure conservation along flux tubes by an enhanced cross-field transport. It demonstrates that the more complex, three-dimensional divertors of stellarators can achieve a similar performance with respect to particle exhaust and detachment like the geometrically simpler poloidal divertors in tokamaks even if the favorable effect of flux amplification is absent. The LTM of the helical divertor depends, however, on the magnetic configuration, i.e. on geometry. It was only observed in the inward shifted configuration with $R_\mathrm{ax} = 3.55$ m, but not in the more frequently studied configuration with $R_\mathrm{ax} = 3.6$ m. A nuclear fusion reactor based on the heliotron concept (DEMO) would benefit from the LTM by the very compact divertor configuration and the excellent performance. |
| Document Type: | article |
| File Description: | electronic resource |
| Language: | English |
| ISSN: | 1741-4326 0029-5515 |
| Relation: | https://doaj.org/toc/0029-5515 |
| DOI: | 10.1088/1741-4326/ad249f |
| Access URL: | https://doaj.org/article/e86016feff0b42efa663f3092dd9eae9 |
| Accession Number: | edsdoj.86016feff0b42efa663f3092dd9eae9 |
| Database: | Directory of Open Access Journals |
| ISSN: | 17414326 00295515 |
|---|---|
| DOI: | 10.1088/1741-4326/ad249f |
| Published in: | Nuclear Fusion |
| Language: | English |