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P: Fachverband Plasmaphysik
P 19: Poster II
P 19.11: Poster
Thursday, March 31, 2022, 16:00–17:30, P
Model for collisional transport of impurities in tokamaks and the combined impact of rotation and collisionality — •Daniel Fajardo1, Clemente Angioni1, Francis Casson2, Anthony Field2, Patrick Maget3, Pierre Manas3, and JET Contributors4 — 1Max-Planck-Institut für Plasmaphysik, Garching, Germany — 2UKAEA/CCFE, Abingdon, United Kingdom — 3CEA/IRFM, Saint Paul-lez-Durance, France — 4See author list of [E. Joffrin et al. 2019 Nucl. Fusion 59 112021]
The collisional transport of impurities in tokamak plasmas can be dominant over the turbulent transport, particularly for heavy impurities like tungsten (W). An analytical model for the Pfirsch-Schlüter (PS) and Banana-Plateau (BP) components of the neoclassical impurity flux has been developed. It is accurate with respect to the drift-kinetic solver NEO across a broad collisional parameter space and reproduces well the profiles of the transport coefficients with experimental ASDEX Upgrade and predicted ITER profiles. The model includes the impact of rotation on the PS transport only. The impact of rotation on the BP transport, relevant at low collisionalities, has received limited consideration so far. The combined effects of rotation, collisionality and trapped particle fraction are analyzed with NEO. It is found that at sufficiently low collisionality and high Mach number an operational window opens where the temperature screening of impurities is enhanced. It is shown that recent experiments at JET have managed to enter this regime. An analytical description of this effect, in particular for the BP flux, is developed for fast integrated modelling applications.