| Autor: |
T.C. Xu, X.Y. Yang, Z.B. Guo, C.J. Xiao, X.G. Wang, R.C. He |
| Předmět: |
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| Zdroj: |
Nuclear Fusion; Jan2020, Vol. 60 Issue 1, p1-1, 1p |
| Abstrakt: |
We report the first experimental observation of zonal flow (ZF) formation through phase patterning. Here the ‘phase’ refers to the eikonal phase carried by streamer-like mode. It is observed that the phase-gradient profile tends to form ‘shock’ layer structures in regions where there are strong streamer-ZF interactions. The emergence of phase-gradient shock layers invalidate the constant-phase-gradient hypothesis, which is frequently employed in the modulational instability models of ZF generation, and is consistent with a recent theoretical work (Guo et al 2016 Phys. Rev. Lett. 117 125002), which predicts that the phase-curvature (gradient of the phase-gradient) can produce a new Reynolds force and accelerate the ZF. By decomposing the Reynolds’ force of the tilted streamers into a phase curvature driven piece and an amplitude inhomogeneity driven one, it is found that inside the shock layers the phase curvature plays a prominent role in accelerating the ZF. We also explore the formation mechanism of the phase pattern and its consistent dynamics with phase-curvature-driven ZF. These findings potentially open a new way to understand the various elusive self-organization phenomena in plasma turbulence. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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