Neoclassical flows in deuterium-helium plasma density pedestals
Journal article, 2017

In tokamak transport barriers, the radial scale of profile variations can be comparable to a typical ion orbit width, which makes the coupling of the distribution function across flux surfaces important in the collisional dynamics. We use the radially global steady-state neoclassical delta f code PERFECT [Landreman et al 2014 Plasma Phys. Control. Fusion 56 045005] to calculate poloidal and toroidal flows, and radial fluxes, in the pedestal. In particular, we have studied the changes in these quantities as the plasma composition is changed from a deuterium bulk species with a helium impurity to a helium bulk with a deuterium impurity, under specific profile similarity assumptions. In the presence of sharp profile variations, the poloidally resolved radial fluxes are important for the total fluxes to be divergence-free, which leads to the appearance of poloidal return-flows. These flows exhibit a complex radial–poloidal structure that extends several orbit widths into the core and is sensitive to abrupt radial changes in the ion temperature gradient. We find that a sizable neoclassical toroidal angular momentum transport can arise in the radially global theory, in contrast to the local.



Neoclassical transport





Stefan Buller

Chalmers, Physics, Subatomic and Plasma Physics

Istvan Pusztai

Chalmers, Physics, Subatomic and Plasma Physics

Sarah Newton

Chalmers, Physics, Subatomic and Plasma Physics

John Omotani

Chalmers, Physics, Subatomic and Plasma Physics

Plasma Physics and Controlled Fusion

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

Vol. 59 5 055019- 055019

Driving Forces

Sustainable development

Areas of Advance



C3SE (Chalmers Centre for Computational Science and Engineering)

Subject Categories

Fusion, Plasma and Space Physics



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