Abstract Details
Abstracts
Author: Virginia Quadri
Requested Type: Consider for Invited
Submitted: 2026-03-01 08:07:33
Co-authors: P. Tamain, Y. Marandet, H. Bufferand, N. Rivals, G. Ciraolo , G.L. Falchetto, R. Düll, S. Sureshkumar, N. Varadarajan, H. Yang, H. Reimerdes, D.S. Oliveira, D. Mancini, L. Casali
Contact Info:
University of Tennessee Knoxville
863 Neyland Dr
Knoxville, Tennessee 37916
United States
Abstract Text:
Three-dimensional fluid turbulence simulations are used to investigate how divertor detachment modifies transport processes in the Scrape-Off Layer and to assess the implications for mean-field models. Simulations are performed with the SOLEDGE3X code, embedding a self-consistent plasma–neutral recycling model, in a long divertor leg geometry representative of TCV. Two operating conditions are considered, corresponding to attached and fully detached outer divertor targets obtained through variations in neutral fueling. Divertor detachment is found to induce significant changes in turbulence characteristics, including fluctuation levels and spatial structure, with strong dependence on poloidal and radial location. Time-averaged density and temperature profiles exhibit substantial SOL broadening and flattening beyond a transition region, reminiscent of experimentally observed shoulder formation. Heat flux profiles systematically show the presence of two decay lengths in the near and far SOL. The presented results clearly shows that in detached conditions, the near SOL decay length increases moderately, while the far SOL contribution is strongly enhanced, both in width and amplitude. Effective perpendicular transport coefficients inferred from the simulations are highly non-uniform, displaying pronounced ballooning features and complex spatial variations in the divertor region. In the detached regime, particle diffusivity increases substantially across the SOL. In contrast, the inferred perpendicular heat conductivity becomes locally negative in the outer divertor leg due to temperature gradient reversals, indicating a breakdown of standard gradient-diffusion closures. Alternative mean-field transport formulations are explored and do not exhibit this limitation. These results raise fundamental questions on the conventional diffusive transport models in high-density detached regimes and highlight the need for improved theoretical description of the edge.
Characterization: 2.0
Comments: