The importance of the classical channel in the impurity transport of optimized stellarators
Artikel i vetenskaplig tidskrift, 2019

In toroidal magnetic confinement devices, such as tokamaks and stellarators, neoclassical transport is usually an order of magnitude larger than its classical
counterpart. However, when a high-collisionality species is present in a stellarator optimized for low Pfirsch–Schlüter current, its classical transport can be comparable
to the neoclassical transport. In this letter, we compare neoclassical and classical fluxes and transport coefficients calculated for Wendelstein 7-X (W7-X) and Large Helical Device (LHD) cases. In W7-X, we find that the classical transport of a collisional impurity is comparable to the neoclassical transport for all radii, while it is negligible in the LHD cases, except in the vicinity of radii where the neoclassical transport changes sign. In the LHD case, electrostatic potential variations on the flux surface significantly enhance the neoclassical impurity transport, while the classical transport is largely insensitive to this effect in the cases studied.

fusion plasma


Stefan Buller

Chalmers, Fysik, Subatomär fysik och plasmafysik

Albert Mollén

Chalmers, Fysik, Subatomär fysik och plasmafysik

Håkan Smith


Istvan Pusztai

Chalmers, Fysik, Subatomär fysik och plasmafysik

Journal of Plasma Physics

0022-3778 (ISSN) 1469-7807 (eISSN)

Vol. 85 4 175850401

Implementation of activities described in the Roadmap to Fusion during Horizon 2020 through a Joint programme of the members of the EUROfusion consortium (EUROfusion)

Europeiska kommissionen (FP7), 2014-01-01 -- 2019-01-01.


Hållbar utveckling




Grundläggande vetenskaper


Fusion, plasma och rymdfysik



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