Recent progress towards a quantitative description of filamentary SOL transport

D. Carralero, M Siccinio, M. Komm, S. A. Artene, F. A. D'Isa, J. Adamek, L. Aho-Mantila, G. Birkenmeier, M. Brix, G Fuchert, M. Groth, T. Lunt, P. Manz, J Madsen, S. Marsen, H.W. Müller, U. Stroth, J.H. Sun, N Vianello, M. WischmeierE. Wolfrum

Research output: Contribution to journalArticleScientificpeer-review

25 Citations (Scopus)

Abstract

A summary of recent results on filamentary transport, mostly obtained with the ASDEX-Upgrade tokamak (AUG), is presented and discussed in an attempt to produce a coherent picture of scrape-off layer (SOL) filamentary transport. A clear correlation is found between L-mode density shoulder formation in the outer midplane and a transition between the sheath-limited and the inertial filamentary regimes. Divertor collisionality is found to be the parameter triggering the transition. A clear reduction of the ion temperature takes place in the far SOL after the transition, both for the background and the filaments. This coincides with a strong variation of the ion temperature distribution, which deviates from Gaussianity and becomes dominated by a strong peak below 5 eV. The filament transition mechanism triggered by a critical value of collisionality seems to be generally applicable to inter-ELM H-mode plasmas, although a secondary threshold related to deuterium fueling is observed. EMC3-EIRENE simulations of neutral dynamics show that an ionization front near the main chamber wall is formed after the shoulder formation. Finally, a clear increase of SOL opacity to neutrals is observed, associated with the shoulder formation. A common SOL transport framework is proposed to account for all these results, and their potential implications for future generation devices are discussed.

Original languageEnglish
Article number056044
JournalNuclear Fusion
Volume57
Issue number5
DOIs
Publication statusPublished - 11 Apr 2017
MoE publication typeA1 Journal article-refereed

Keywords

  • ASDEX-Upgrade
  • filaments
  • main wall recycling
  • SOL transport

Fingerprint Dive into the research topics of 'Recent progress towards a quantitative description of filamentary SOL transport'. Together they form a unique fingerprint.

Cite this