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Physics of Island Divertor Plasmas in Stellarators
Author(s) -
Feng Y.,
Sardei F.,
Grigull P.,
McCormick K.,
Kisslinger J.,
Reiter D.
Publication year - 2006
Publication title -
contributions to plasma physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.531
H-Index - 47
eISSN - 1521-3986
pISSN - 0863-1042
DOI - 10.1002/ctpp.200610037
Subject(s) - divertor , stellarator , tokamak , plasma , physics , impurity , consistency (knowledge bases) , nuclear physics , atomic physics , flux (metallurgy) , core (optical fiber) , computational physics , nuclear engineering , materials science , geometry , optics , quantum mechanics , metallurgy , engineering , mathematics
Using the W7‐AS island divertor as a guideline, the paper presents a physics‐analysis of the plasma, neutral and impurity transport in the island divertor, aimed at showing the basic similarities and differences in SOLtransport between tokamaks and a typical helical device. Discussion is mainly based on simple models and estimations, while 3D modeling calculations serve only for control of self‐consistency and for determining basic functional dependencies not accessible otherwise. The paper focuses on the explanation of the governing physics and mechanisms for the SOL or SOL‐related phenomena in W7‐AS, such as the absence of a high‐recycling regime, rollover of the total recycling flux and of the core‐fueling rate from the recycling neutrals, island neutral screening, partial detachment, geometry‐related detachment stability and Marfes. A special emphasis is given on a stellarator‐specific, impurity retention effect of the edge islands recently obtained by EMC3/EIRENE simulations for high‐density, high‐confinement plasmas. The paper presents a theoretical analysis of the island divertor physics, with most key issues, however, being related to experimental results. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)