Global effects on neoclassical transport in the pedestal with impurities
Artikel i vetenskaplig tidskrift, 2016

We present a numerical study of collisional transport in a tokamak pedestal in the presence of non-trace impurities, using the radially global delta-f neoclassical solver PERFECT [M. Landreman et al. 2014 Plasma Phys. Control. Fusion 56 045005]. It is known that in a tokamak core with non-trace impurities present the radial impurity flux opposes the bulk ion flux to provide an ambipolar particle transport, with the electron transport being negligibly small. However, in a sharp density pedestal with sub-sonic ion flows the electron transport can be comparable to the ion and impurity flows. Furthermore, the neoclassical particle transport is not intrinsically ambipolar, and the non-ambipolarity of the fluxes extends outside the pedestal region by the radial coupling of the perturbations. The neoclassical momentum transport, which is finite in the presence of ion orbit-width scale profile variations, is significantly enhanced when impurities are present in non-trace quantities, even if the total parallel mass flow is dominated by the bulk ions.

radially global

neoclassical transport


tokamak pedestal

momentum transport


Istvan Pusztai

Chalmers, Fysik, Subatomär fysik och plasmafysik

Stefan Buller

Chalmers, Fysik, Subatomär fysik och plasmafysik

Matt Landreman

University of Maryland

Plasma Physics and Controlled Fusion

0741-3335 (ISSN) 1361-6587 (eISSN)

Vol. 58 085001-


Hållbar utveckling




Fusion, plasma och rymdfysik