| Autor: |
J. Das, Ulrich Stroth, D. Hildebrandt, O. Heinrich, H. Niedermeyer, H. Verbeek, Friedrich E. Wagner, J. V. Hofmann, R. Schneider, Y. Feng, C. De Michaelis, R. Brakel, NBI-Group, Robert Wolf, F. Sardei, G. Herre, W AS-Team, P. Ghendrih, C. Grisolia, P. Grigull, G. Kuehner, J. Kisslinger, M. Richter-Gloetzl, J. Geiger |
| Rok vydání: |
1997 |
| Předmět: |
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| Zdroj: |
Journal of Nuclear Materials. :135-148 |
| ISSN: |
0022-3115 |
| DOI: |
10.1016/s0022-3115(97)80036-0 |
| Popis: |
Basic topological features of the island divertor concept for low shear stellarators are discussed with emphasis on the differences to tokamak divertors. Extensive measurements of the edge structures by two-dimensional plasma spectroscopy and by target calorimetry are in excellent agreement with predicted vacuum and equilibrium configurations, which are available up to central β values of ∼ 1%. For this β value the calculated field-line pitch inside the islands is twice that of the corresponding vacuum case. Video observations of the strike points indicate stability of the island structures for central β values up to ∼ 3.7%. The interpretation of the complex island divertor physics of W7-AS has become possible by the development of the three-dimensional plasma transport code EMC3 (Edge Monte Carlo 3D), which has been coupled self-consistently to the EIRENE neutral gas code. Analysis of high density NBI discharges gives strong indications of stable high recycling conditions for n e ≥ 10 20 m −3 . The observations are reproduced by the EMC3/EIRENE code and supported by calculations with the B2/EIRENE code adapted to W7-AS. Improvement of recycling, pumping and target load distribution is expected from the new optimized target plates and baffles to be installed in W7-AS. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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Full Text from ScienceDirect