Multiscale Chirping Modes Driven by Thermal Ions in a Plasma with Reactor-Relevant Ion Temperature

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Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2021-07-07
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Language
en
Pages
6
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Physical Review Letters, Volume 127, issue 2
Abstract
A thermal ion driven bursting instability with rapid frequency chirping, considered as an Alfvénic ion temperature gradient mode, has been observed in plasmas having reactor-relevant temperature in the DIII-D tokamak. The modes are excited over a wide spatial range from macroscopic device size to microturbulence size and the perturbation energy propagates across multiple spatial scales. The radial mode structure is able to expand from local to global in ∼0.1 ms and it causes magnetic topology changes in the plasma edge, which can lead to a minor disruption event. Since the mode is typically observed in the high ion temperature ≳10 keV and high-β plasma regime, the manifestation of the mode in future reactors should be studied with development of mitigation strategies, if needed. This is the first observation of destabilization of the Alfvén continuum caused by the compressibility of ions with reactor-relevant ion temperature.
Description
Funding Information: The author (X. D. Du) would like to thank F. Zonca and L. Chen for fruitful discussions. This work was supported by the US DOE under DE-AC05-00OR22725, DE-FC02-04ER54698, DE-AC02-09CH11466, DE-SC0015878, and DE-SC0018287. Publisher Copyright: © 2021 American Physical Society.
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Du , X D , Hong , R J , Heidbrink , W W , Jian , X , Wang , H , Eidietis , N W , Van Zeeland , M A , Austin , M E , Liu , Y Q , Crocker , N A , Rhodes , T L , Särkimäki , K , Snicker , A , Wu , W & Knolker , M 2021 , ' Multiscale Chirping Modes Driven by Thermal Ions in a Plasma with Reactor-Relevant Ion Temperature ' , Physical Review Letters , vol. 127 , no. 2 , 025001 . https://doi.org/10.1103/PhysRevLett.127.025001