[Table of Contents]

Plasma and Fusion Research

Volume 5, 011 (2010)

Regular Articles

Theoretical Modeling of Transport Barriers in Helical Plasmas
Shinichiro TODA, Kimitaka ITOH and Nobuyoshi OHYABU
National Institute for Fusion Science, Toki 509-5292, Japan
(Received 11 August 2009 / Accepted 3 February 2010 / Published 29 March 2010)

Abstract

A unified transport model is proposed to study the physical mechanism for the formation of electron internal transport barriers (e-ITB) in helical plasmas and internal diffusion barriers (IDB) observed in the Large Helical Device (LHD). An e-ITB can be predicted with the effect of zonal flows (ZFs) in the low collisional regime when the radial variation in particle turbulent diffusivity is included. The transport analysis in this article shows that particle fueling induces IDB formation when the unified transport model is used in the high collisional regime. After particle fueling, a steep density gradient forms. To examine the density limit for the IDB in helical toroidal plasmas, the effect of radiation loss is included in a set of transport equations.

Keywords

helical plasma, turbulent transport, transport barrier, radial electric field, density limit

DOI: 10.1585/pfr.5.011

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This paper may be cited as follows:

Shinichiro TODA, Kimitaka ITOH and Nobuyoshi OHYABU, Plasma Fusion Res. 5, 011 (2010).