TY - JOUR
T1 - Turbulence in the near scrape-off layer towards the L-mode density limit in ASDEX-Upgrade
AU - ASDEX Upgrade Team
AU - Grenfell, G.
AU - Manz, P.
AU - Conway, G. D.
AU - Eich, T.
AU - Adamek, J.
AU - Brida, D.
AU - Komm, M.
AU - Nishizawa, T.
AU - Griener, M.
AU - Tal, B.
AU - Stroth, U.
N1 - Funding Information:
This work has been carried out within the framework of the EUROfusion Consortium, funded by the European Union via the Euratom Research and Training Programme (Grant Agreement No 101052200 — EUROfusion). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Commission. Neither the European Union nor the European Commission can be held responsible for them.
Publisher Copyright:
© 2022 The Authors
PY - 2022/10
Y1 - 2022/10
N2 - The L-mode density limit in ASDEX Upgrade is investigated with focus on the scrape-off layer. We observe a chain of events that involves the collapse of the E×B outer shear layer (just outside the separatrix), widening of the electron pressure fall-off length, outer divertor detachment, density shoulder formation, reduction and flattening of the parallel Mach number, and enhanced turbulent cross-field transport. The latter effect was associated with higher amplitude density fluctuations at low frequencies, where the turbulent cross-phase between density and velocity fluctuations pointing radially outward was favourable.
AB - The L-mode density limit in ASDEX Upgrade is investigated with focus on the scrape-off layer. We observe a chain of events that involves the collapse of the E×B outer shear layer (just outside the separatrix), widening of the electron pressure fall-off length, outer divertor detachment, density shoulder formation, reduction and flattening of the parallel Mach number, and enhanced turbulent cross-field transport. The latter effect was associated with higher amplitude density fluctuations at low frequencies, where the turbulent cross-phase between density and velocity fluctuations pointing radially outward was favourable.
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U2 - 10.1016/j.nme.2022.101277
DO - 10.1016/j.nme.2022.101277
M3 - Article
AN - SCOPUS:85141272924
VL - 33
JO - Nuclear Materials and Energy
JF - Nuclear Materials and Energy
SN - 2352-1791
M1 - 101277
ER -