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Verification of Background Noise Estimation Method in W-Band Millimeter-Wave Back-Scattering System

Tatsuhiro NASU^1,2), Tokihiko TOKUZAWA^1,2,3), Daiki NISHIMURA²⁾, Ryoma YANAI²⁾

1)

Department of Fusion Science, The Graduate University for Advanced Studies, Toki 509-5292, Japan

2)

National Institute for Fusion Science, National Institutes of Natural Sciences, Toki 509-5292, Japan

3)

Research Institute for Applied Mechanics, Kyusyu University, Kasuga 816-8580, Japan

(Received 27 August 2025 / Accepted 9 October 2025 / Published 17 December 2025)

Abstract

Millimeter-wave back-scattering (BS) system is a diagnostics system capable of measuring electron-scale turbulence, which is expected to have a large influence on future burning plasma confinement. The measured frequency band overlaps that of the electron cyclotron emission (ECE), resulting in comparable background noise. We have developed a method to estimate this background noise by implementing linear regression between the BS signal intensity and that of the ECE when the probing beam is turned off, and have verified the method in LHD experiments.

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

Keywords

millimeter-wave back-scattering, electron cyclotron emission, electron-scale turbulence, Large Helical Device

DOI: 10.1585/pfr.20.1202056

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References

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