[Table of Contents]

Plasma and Fusion Research

Volume 3, S1066 (2008)

Regular Articles

Two-Fluid Flowing Equilibria of Helicity Injected Spherical Torus with Non-Uniform Density
Takashi KANKI, Loren C. STEINHAUER1) and Masayoshi NAGATA2)
Department of Maritime Science and Technology, Japan Coast Guard Academy, Kure, Hiroshima 737-8512, Japan
1)
University of Washington, Redmond Plasma Physics Laboratory, Redmond, Washington 98052, USA
2)
Department of Electrical Engineering and Computer Sciences, University of Hyogo, Himeji, Hyogo 671-2201, Japan
(Received 8 November 2007 / Accepted 19 March 2008 / Published 4 August 2008)

Abstract

Two-dimensional two-fluid flowing equilibria of helicity-injected spherical torus with non-uniform density and both toroidal and poloidal flows for each species have been numerically determined by the nearby-fluids procedure. It is found from the numerical results that the equilibrium for the driven λ (≡ μ0 j·B/B2 ) profile exhibits a diamagnetic toroidal field, high-β (toroidal beta value, βt = 32%), hollow current profile, and centrally broad density. In contrast, the decaying equilibrium exhibits a paramagnetic toroidal field, low-β (βt = 10%), centrally peaked current profile, and density with a steep gradient in the outer edge region. In the driven case, the toroidal ion and electron flows are in the same direction, and two-fluid effects are less important since the E × B drift is dominant. In the decaying case, the toroidal ion and electron flows are opposite in the outer edge region, and two-fluid effects are significant locally in the edge due to the ion diamagnetic drift.

Keywords

helicity injection, equilibrium, plasma flow, two-fluid effect, E × B drift, diamagnetic drift

DOI: 10.1585/pfr.3.S1066

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This paper may be cited as follows:

Takashi KANKI, Loren C. STEINHAUER and Masayoshi NAGATA, Plasma Fusion Res. 3, S1066 (2008).