Development and Application of Collective Thomson Scattering Diagnostics for Energetic and Bulk Ion Measurements in the Large Helical Device

Résumé fourni par la source

To diagnose energetic and bulk ions in fusion plasmas, we have developed a millimeter-wave collective Thomson scattering (CTS) diagnostic system utilizing a megawatt-class gyrotron, originally designed for electron cyclotron heating (ECH), in the Large Helical Device (LHD). This paper presents CTS measurements of energetic and anisotropic ions produced by neutral beam injection (NBI), along with a method for analyzing CTS spectra. In addition, we report on the development of a 303 GHz gyrotron intended for CTS diagnostics, which enables lower background radiation levels and improved signal-to-noise ratio (SNR) in the detection of scattered signals.which is expected to reduce background radiation and improve the signal-to-noise ratio in CTS measurements. Furthermore, a high-performance notch filter has been developed to block stray radiation from the gyrotron beam within the vacuum vessel, preventing it from entering the receiver as noise. This type of notch filter is employed not only in CTS measurements but also in electron cyclotron emission (ECE) and correlation ECE diagnostics. This paper outlines these developments and their application to energetic ion diagnostics in LHD plasmas.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.