Modification of SOL profiles and fluctuations with line-average density and divertor flux expansion in TCV
- University degli Studi di Padova (Italy); Ecole Polytechnique Federale Lausanne (EPFL) (Switzerland). Swiss Plasma Center
- University of California San Diego, La Jolla, CA (United States); Ecole Polytechnique Federale Lausanne (EPFL) (Switzerland). Swiss Plasma Center
- Ecole Polytechnique Federale Lausanne (EPFL) (Switzerland). Swiss Plasma Center
- Culham Science Centre, Abingdon (United Kingdom). Culham Centre for Fusion Energy (CCFE)
- University of California San Diego, La Jolla, CA (United States)
- University of York (United Kingdom)
- Dutch Institute for Fundamental Energy Research, Eindhoven (Netherlands)
- University Innsbruck (Austria)
- Jozef Stefan Institute, Ljubljana (Slovenia)
- Technical University of Denmark, Lyngby (Denmark)
- University degli Studi di Padova (Italy)
- Max Planck Institute for Plasma Physics, Garching (Germany)
A set of Ohmic density ramp experiments addressing the role of parallel connection length in modifying scrape off layer (SOL) properties has been performed on the TCV tokamak. The parallel connection length has been modified by varying the poloidal flux expansion fx. It will be shown that this modification does not influence neither the detachment density threshold, nor the development of a flat SOL density profile which instead depends strongly on the increase of the core line average density. The modification of the SOL upstream profile, with the appearance of what is generally called a density shoulder, has been related to the properties of filamentary blobs. Blob size increases with density, without any dependence on the parallel connection length both in the near and far SOL. The increase of the density decay length, corresponding to a profile flattening, has been related to the variation of the divertor normalized collisionality Λdiv, showing that in TCV the increase of Λdiv is not sufficient to guarantee the SOL upstream profile flattening.
- Research Organization:
- University of California San Diego, La Jolla, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC); EUROfusion Consortium
- Contributing Organization:
- TCV Team; EUROfusion MST1 Team
- Grant/Contract Number:
- SC0010529; 633053
- OSTI ID:
- 1540522
- Journal Information:
- Nuclear Fusion, Vol. 57, Issue 11; ISSN 0029-5515
- Publisher:
- IOP ScienceCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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