Parallel impurity dynamics in the TJ-II stellarator
Abstract
We review in a tutorial fashion some of the causes of impurity density variations along field lines and radial impurity transport in the moment approach framework. An explicit and compact form of the parallel inertia force valid for arbitrary toroidal geometry and magnetic coordinates is derived and shown to be non-negligible for typical TJ-II plasma conditions. In the second part of the article, we apply the fluid model including main ion-impurity friction and inertia to observations of asymmetric emissivity patterns in neutral beam heated plasmas of the TJ-II stellarator. The model is able to explain qualitatively several features of the radiation asymmetry, both in stationary and transient conditions, based on the calculated in-surface variations of the impurity density.
Keywords
Cite
@article{arxiv.1604.05914,
title = {Parallel impurity dynamics in the TJ-II stellarator},
author = {J A Alonso and J L Velasco and I Calvo and T Estrada and J M Fontdecaba and J M García-Regaña and J Geiger and M Landreman and K J McCarthy and F Medina and B Ph Van Milligen and M A Ochando and F I Parra and the TJ-II Team and the W7-X Team},
journal= {arXiv preprint arXiv:1604.05914},
year = {2016}
}