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Spatial Structure of Low-Frequency Hall-MHD Wave Propagation in a Field-Reversed Configuration Plasma

Takuya TAKAHASHI¹⁾, Toru TAKAHASHI¹⁾, Toshiki TAKAHASHI¹⁾, Siyu ZHANG¹⁾, Shun INOUE¹⁾, Tomohiko ASAI²⁾, Naoki MIZUGUCHI³⁾

1)

Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan

2)

College of Science and Technology, Nihon University, Tokyo 101-8308, Japan

3)

National Institute for Fusion Science, National Institutes of Natural Sciences, 322-6 Oroshi-cho, Toki, Gifu 509-5292, Japan

(Received 27 June 2025 / Accepted 3 July 2025 / Published 10 September 2025)

Abstract

A linear Hall-MHD simulation code is developed to investigate the spatial structure of two-dimensional wave propagation excited in a field-reversed configuration (FRC) equilibrium plasma. A low-frequency oscillating magnetic field at 160 kHz is externally applied by a ring coil installed concentrically with the device axis in the open-field region. The generated toroidal magnetic field propagates primarily along magnetic field lines at a phase velocity comparable to that of shear Alfvén waves. Due to the Hall effect, toroidal magnetic fluctuations penetrate into the closed-field region near the separatrix over a distance on the order of the ion skin depth. In the core region, where magnetic fluctuations vanish, ion density oscillations become dominant.

Copyright (c) 2025 The Japan Society of Plasma Science and Nuclear Fusion Research

Keywords

Hall-MHD, low-frequency wave, field-reversed configuration, numerical simulation

DOI: 10.1585/pfr.20.1203042

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References

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