Plasma and Fusion Research

Volume 14, 2403010 (2019)

Regular Articles

Spontaneous Ion Temperature Gradient in Inhomogeneous Magnetic Fields and Its Effect on the Parallel Heat Transport
Satoshi TOGO, Tomonori TAKIZUKA1), Mizuki SAKAMOTO, Naomichi EZUMI, Yuichi OGAWA2), Kenzo IBANO1), Kunpei NOJIRI, Takaaki IIJIMA, Yosuke KINOSHITA, Toshiki HARA and Yousuke NAKASHIMA
Plasma Research Center, University of Tsukuba, Tsukuba 305-8577, Japan
1)
Graduate School of Engineering, Osaka University, Suita 565-0871, Japan
2)
Graduate School of Frontier Sciences, University of Tokyo, Kashiwa 277-8568, Japan
(Received 30 September 2018 / Accepted 4 December 2018 / Published 24 January 2019)

Abstract

A new closure model for the parallel conductive heat flux of the perpendicular component of ion energy (qi,⊥) is proposed which considers the effect of the spontaneous parallel gradient of the perpendicular ion temperature in inhomogeneous magnetic fields. Profiles of plasma parameters and the particle confinement efficiency are compared between the new qi,⊥ model and a conventional one in a simple mirror system. It is found that the conservation of the magnetic moment is reproduced with the new qi,⊥ model. Comparisons of ion power flux profiles show that the new qi,⊥ model changes the direction of qi,⊥ keeping the spontaneous parallel gradient of the perpendicular ion temperature. Almost linear relations between the particle confinement time and the ion-ion Coulomb collision time are also obtained with both qi,⊥ models.

Keywords

plasma fluid model, closure model, conductive heat flux, ion temperature anisotropy, inhomogeneous magnetic field, mirror effect, magnetic moment

DOI: 10.1585/pfr.14.2403010

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