[Table of Contents]

Plasma and Fusion Research

Volume 7, 2403104 (2012)

Regular Articles

Analysis of ECRH Pre-Ionization for Plasma Start-Up in JT-60SA
Kazuyoshi HADA, Kazunobu NAGASAKI1), Kai MASUDA1), Ryota KINJO, Shunsuke IDE2) and Akihiko ISAYAMA2)
Graduate School of Energy Science, Kyoto University, Uji, Kyoto 611-0011, Japan
1)
Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan
2)
Japan Atomic Energy Agency, Naka, Ibaraki 311-0193, Japan
(Received 9 December 2011 / Accepted 31 May 2012 / Published 26 July 2012)

Abstract

Plasma start-up assisted by electron cyclotron resonance heating (ECRH) pre-ionization is theoretically studied for the superconducting tokamak JT-60SA by using a zero-dimensional (0-D) model. Because the toroidal electric field is limited to 0.5 Vm−1, we clarify the conditions for a robust plasma initiation. Five temporal equations are solved for a spatially-uniform plasma: the electron and neutral density equations, the electron and ion energy density equations, and the electric circuit equation. The numerical calculation results show that an absorbed ECRH power of 150 kW is required to start up the plasma, assuming an initial neutral density of 3.0 × 1018 m−3, and that reducing the oxygen and carbon impurity densities facilitates successful start-up. We discuss the dependence of the absorbed ECRH power on the neutral density and impurities. The simulation qualitatively reproduces experimental results from JT-60U.

Keywords

pre-ionization, electron cyclotron resonance heating, superconducting tokamak, JT-60SA, zero-dimensional model

DOI: 10.1585/pfr.7.2403104

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This paper may be cited as follows:

Kazuyoshi HADA, Kazunobu NAGASAKI, Kai MASUDA, Ryota KINJO, Shunsuke IDE and Akihiko ISAYAMA, Plasma Fusion Res. 7, 2403104 (2012).