Internal Transport Barrier Triggered by Neoclassical Transport in W7-AS

U. Stroth; K. Itoh; S.-I. Itoh; H. Hartfuss; H. Laqua; the ECRH team; the W7-AS team

doi:10.1103/PhysRevLett.86.5910

Internal Transport Barrier Triggered by Neoclassical Transport in W7-AS

U. Stroth, K. Itoh, S.-I. Itoh, H. Hartfuss, H. Laqua, the ECRH team, and the W7-AS team

Phys. Rev. Lett. 86, 5910 – Published 25 June 2001

Abstract

The three-dimensional magnetic configuration of a stellarator offers two specific mechanisms for a transition to improved particle and energy confinement. One route goes through the so-called electron-root confinement regime, which leads to a reduction of neoclassical transport via strong radial electric fields. In this Letter evidence for a second route is presented. It opens due to the layer of a strongly varying radial electric field which is present in the transitional region from neoclassical electron to ion-root confinement. This type of improvement acts on turbulent transport.

Received 23 October 2000

DOI:https://doi.org/10.1103/PhysRevLett.86.5910

Authors & Affiliations

U. Stroth², K. Itoh³, S.-I. Itoh⁴, H. Hartfuss¹, H. Laqua¹, the ECRH team¹, and the W7-AS team¹

¹Max-Planck-Institut für Plasmaphysik, EURATOM Association, D-85748 Garching, Germany
²Institut für Experimentelle und Angewandte Physik, CAU Kiel, 24098 Kiel, Germany
³National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292, Japan
⁴Kyushu University, Kasuga 816-8580, Japan