Plasma and Fusion Research

Volume 15, 2402015 (2020)

Regular Articles

Schemes for ICRF Heating of High-Density Core Plasma in LHD
Kenji SAITO1,2), Ryosuke SEKI1,2), Shuji KAMIO1), Hiroshi KASAHARA1) and Tetsuo SEKI1)
1)
National Institute for Fusion Science, National Institutes of Natural Sciences, Toki, Gifu 509-5292, Japan
2)
Department of Fusion Science, The Graduate University for Advanced Studies, SOKENDAI, Toki, Gifu 509-5292, Japan
(Received 27 November 2019 / Accepted 17 February 2020 / Published 14 April 2020)

Abstract

Ion Cyclotron Range of Frequencies (ICRF) heating is one of the plasma heating methods in the Large Helical Device (LHD). The wave injected from the ICRF antenna can propagate in the plasma even if the plasma density is extremely high. It was shown that the high power absorption occurs in the plasma core with the second harmonic heating in the case of high-density deuterium plasma in LHD by the calculation with a simple model of the ICRF heating. Wave number perpendicular to the static magnetic field increases with the plasma density, and it enhances the finite Larmor radius effect in the second harmonic heating. Enhanced finite Larmor radius effect and a large amount of resonant ions enable the intense power absorption. By increasing the frequency, the third harmonic heating will also be possible. Though the intensity of the power absorption will decrease, more localized heating on the magnetic axis will be realized because the finite Larmor radius effect works better in the third harmonic heating.

Keywords

Large Helical Device, ICRF heating, second harmonic heating, third harmonic heating, internal diffusion barrier, simple-model simulation

DOI: 10.1585/pfr.15.2402015

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