Recent progress towards a quantitative description of filamentary SOL transport
Abstract
A summary of recent results on filamentary transport, mostly obtained in the ASDEX-Upgrade tokamak (AUG), is presented and discussed in an attempt to produce a coherent picture of 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 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 to the shoulder formation. A common SOL transport framework is proposed account for all these results, and their potential implications for future generation devices are discussed.
Keywords
Cite
@article{arxiv.2005.06250,
title = {Recent progress towards a quantitative description of filamentary SOL transport},
author = {D. Carralero and M. Siccinio and M. Komm and S. A. Artene and F. A. D'Isa and J. Adamek and L. Aho-Mantila and G. Birkenmeier and M. Brix and G. Fuchert and M. Groth and T. Lunt and P. Manz and J. Madsen and S. Marsen and H. W. Müller and U. Stroth and H. J. Sun and N. Vianello and M. Wischmeier and E. Wolfrum and ASDEX Upgrade Team and COMPASS Team and JET Contributors and the EUROfusion MST team},
journal= {arXiv preprint arXiv:2005.06250},
year = {2020}
}
Comments
Published in Nuclear Fusion