Experimental Investigations of Quasi-Coherent Micro-Instabilities in J-TEXT Ohmic Plasmas

Quasi-coherent micro-instabilities is one of the key topics of magnetic confinement fusion. This work focuses on the quasi-coherent spectra of ion temperature gradient (ITG) and trapped-electron-mode instabilities using newly developed far-forward collective scattering measurements within ohmic plas...

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Bibliographic Details
Published inChinese physics letters Vol. 41; no. 5; pp. 55201 - 52
Main Authors Shi, Peng, Zhuang, G., Cheng, Zhifeng, Gao, Li, Zhou, Yinan, Liu, Yong, Luo, J. T., Li, Jingchun
Format Journal Article
LanguageEnglish
Published Chinese Physical Society and IOP Publishing Ltd 01.05.2024
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ISSN0256-307X
1741-3540
DOI10.1088/0256-307X/41/5/055201

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Summary:Quasi-coherent micro-instabilities is one of the key topics of magnetic confinement fusion. This work focuses on the quasi-coherent spectra of ion temperature gradient (ITG) and trapped-electron-mode instabilities using newly developed far-forward collective scattering measurements within ohmic plasmas in the J-TEXT tokamak. The ITG mode is characterized by frequencies ranging from 30 to 100 kHz and wavenumbers ( k θ ρ s ) less than 0.3. Beyond a critical plasma density threshold, the ITG mode undergoes a bifurcation, which is marked by a reduction in frequency and an enhancement in amplitude. Concurrently, enhancements in ion energy loss and degradation in confinement are observed. This ground-breaking discovery represents the first instance of direct experimental evidence that establishes a clear link between ITG instability and ion thermal transport.
ISSN:0256-307X
1741-3540
DOI:10.1088/0256-307X/41/5/055201