Neoclassical flows in deuterium-helium plasma density pedestals
Artikel i vetenskaplig tidskrift, 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.

fusion

flows

Neoclassical transport

tokamak

helium

deuterium

Författare

Stefan Buller

Chalmers, Fysik, Subatomär fysik och plasmafysik

Istvan Pusztai

Chalmers, Fysik, Subatomär fysik och plasmafysik

Sarah Newton

Chalmers, Fysik, Subatomär fysik och plasmafysik

John Omotani

Chalmers, Fysik, Subatomär fysik och plasmafysik

Plasma Physics and Controlled Fusion

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

Vol. 59 5 055019-

Drivkrafter

Hållbar utveckling

Styrkeområden

Energi

Infrastruktur

C3SE (Chalmers Centre for Computational Science and Engineering)

Ämneskategorier

Fusion, plasma och rymdfysik

DOI

10.1088/1361-6587/aa658a

Mer information

Skapat

2017-10-08