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Interchange‐turbulence‐based radial transport model for SOLPS‐ITER: A COMPASS case study
Author(s) -
Carli Stefano,
Dekeyser Wouter,
Coosemans Reinart,
Dejarnac Renaud,
Komm Michael,
Dimitrova Miglena,
Adámek Jiří,
Bílková Petra,
Böhm Petr
Publication year - 2020
Publication title -
contributions to plasma physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.531
H-Index - 47
eISSN - 1521-3986
pISSN - 0863-1042
DOI - 10.1002/ctpp.201900155
Subject(s) - turbulence , closure (psychology) , upstream (networking) , physics , diffusion , statistical physics , mechanics , plasma , computer science , thermodynamics , nuclear physics , computer network , economics , market economy
Mean‐field plasma edge transport codes such as SOLPS‐ITER heavily rely on ad‐hoc radial diffusion coefficients to approximately model anomalous transport. Such coefficients are experimentally determined and vary between different machines, and also depend on the operational regime and plasma location within the same device. Therefore, to match experimental data the modeller is required to manually tune several free parameters in expensive simulations, and the code's predictive capabilities are significantly downgraded. As a solution, a new model has been developed for SOLPS‐ITER, solving an additional transport equation for the turbulent kinetic energy k , derived by consistently time‐averaging the Braginskii equations, and including a diffusive closure for the anomalous particle flux. This closure model relates the anomalous diffusion coefficient to the local k value. The resulting equation structure and its closure are inspired by TOKAM2D isothermal interchange turbulence simulation results. Within this model, fewer and hopefully more universal free parameters are retained, thus improving the code's predictive capabilities. The new model has been tested on a COMPASS case for which upstream plasma profiles were available. Experimental data and a reference solution, obtained by matching the profiles through manual tuning of radial diffusivities, have been used to estimate the parameters of our new transport model. A ballooned particle diffusivity profile is retrieved by the new radial transport model, thanks to the proposed interchange drive. The obtained upstream profiles qualitatively agree with the experiment and prove the new model is a promising first attempt to be further refined.