The importance of the classical channel in the impurity transport of optimized stellarators

The importance of the classical channel in the impurity transport of optimized stellarators

The importance of the classical channel in the impurity transport of optimized stellarators 150 150 UKAEA Opendata
UKAEA-CCFE-PR(19)53

The importance of the classical channel in the impurity transport of optimized stellarators

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 an 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 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. Even for the LHD case – which has not been optimized for low Pfirsch-Schlüter current – the classical transport can still be comparable to the neoclassical at specific radii.

Collection:
Journals
Journal:
Journal of Plasma Physics
Publisher:
Cambridge University Press
Published date:
26/04/2024