Enhancement and suppression of turbulence by energetic-particle-driven geodesic acoustic modes
| العنوان: | Enhancement and suppression of turbulence by energetic-particle-driven geodesic acoustic modes |
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| المؤلفون: | Naohiro Kasuya, Makoto Sasaki, Klaus Hallatschek, Kimitaka Itoh, Maxime Lesur, Yusuke Kosuga, S.-I. Itoh |
| المصدر: | Scientific Reports, Vol 7, Iss 1, Pp 1-7 (2017) Scientific Reports |
| بيانات النشر: | Springer Science and Business Media LLC, 2017. |
| سنة النشر: | 2017 |
| مصطلحات موضوعية: | Physics, Multidisciplinary, Geodesic, Turbulence, lcsh:R, Dynamics (mechanics), lcsh:Medicine, Trapping, Mechanics, Characteristic velocity, 01 natural sciences, Article, 010305 fluids & plasmas, Nonlinear Sciences::Chaotic Dynamics, Physics::Fluid Dynamics, Phase space, Physics::Space Physics, 0103 physical sciences, Particle, lcsh:Q, Phase velocity, lcsh:Science, 010306 general physics |
| الوصف: | We propose a novel mechanism of enhancement of turbulence by energetic-particle-driven geodesic acoustic modes (EGAMs). The dynamics of drift-wave-type turbulence in the phase space is investigated by wave-kinetic equation. Spatially inhomogeneous turbulence in the presence of a transport barrier is considered. We discovered that trapping of turbulence clumps by the EGAMs is the key parameter that determines either suppress or enhance turbulence. In regions where turbulence is unstable, EGAM suppresses the turbulence. In contrast, in the stable region, EGAM traps clumps of turbulence and carries them across the transport barrier, so that the turbulence can be enhanced. The turbulence trapped by EGAMs can propagate independent of the gradients of density and temperature, which leads to non-Fickian transport. Hence, there appear a new global characteristic velocity, the phase velocity of GAMs, for turbulence dynamics, in addition to the local group velocity and that of the turbulence spreading. With these effect, EGAMs can deteriorate transport barriers and affect turbulence substantially. This manuscript provides a basis to consider whether a coherent wave breaks or strengthen transport barriers. |
| وصف الملف: | application/pdf |
| تدمد: | 2045-2322 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::689ec20946ab3cfaeb5fc7aae8351a1f https://doi.org/10.1038/s41598-017-17011-y |
| حقوق: | OPEN |
| رقم الأكسشن: | edsair.doi.dedup.....689ec20946ab3cfaeb5fc7aae8351a1f |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 20452322 |
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