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Title: Turbulence Spreading into Linearly Stable Zone and Transport Scaling

Abstract

We study the simplest problem of turbulence spreading corresponding to the spatio-temporal propagation of a patch of turbulence from a region where it is locally excited to a region of weaker excitation, or even local damping. A single model equation for the local turbulence intensity I(x, t) includes the effects of local linear growth and damping, spatially local nonlinear coupling to dissipation and spatial scattering of turbulence energy induced by nonlinear coupling. In the absence of dissipation, the front propagation into the linearly stable zone occurs with the property of rapid progression at small t, followed by slower subdiffusive progression at late times. The turbulence radial spreading into the linearly stable zone reduces the turbulent intensity in the linearly unstable zone, and introduces an additional dependence on the rho* is always equal to rho i/a to the turbulent intensity and the transport scaling. These are in broad, semi-quantitative agreements with a number of global gyrokinetic simulation results with zonal flows and without zonal flows. The front propagation stops when the radial flux of fluctuation energy from the linearly unstable region is balanced by local dissipation in the linearly stable region.

Authors:
; ; ; ;
Publication Date:
Research Org.:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Org.:
USDOE Office of Science (SC) (US)
OSTI Identifier:
820109
Report Number(s):
PPPL-3887
TRN: US0305686
DOE Contract Number:  
AC02-76CH03073
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 20 Oct 2003
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; DAMPING; EXCITATION; FLUCTUATIONS; SCATTERING; SIMULATION; TRANSPORT; TURBULENCE; DIFFUSION, ANOMALOUS; TRANSPORT PHENOMENA

Citation Formats

Hahm, T S, Diamond, P H, Lin, Z, Itoh, K, and Itoh, S -I. Turbulence Spreading into Linearly Stable Zone and Transport Scaling. United States: N. p., 2003. Web. doi:10.2172/820109.
Hahm, T S, Diamond, P H, Lin, Z, Itoh, K, & Itoh, S -I. Turbulence Spreading into Linearly Stable Zone and Transport Scaling. United States. https://doi.org/10.2172/820109
Hahm, T S, Diamond, P H, Lin, Z, Itoh, K, and Itoh, S -I. 2003. "Turbulence Spreading into Linearly Stable Zone and Transport Scaling". United States. https://doi.org/10.2172/820109. https://www.osti.gov/servlets/purl/820109.
@article{osti_820109,
title = {Turbulence Spreading into Linearly Stable Zone and Transport Scaling},
author = {Hahm, T S and Diamond, P H and Lin, Z and Itoh, K and Itoh, S -I},
abstractNote = {We study the simplest problem of turbulence spreading corresponding to the spatio-temporal propagation of a patch of turbulence from a region where it is locally excited to a region of weaker excitation, or even local damping. A single model equation for the local turbulence intensity I(x, t) includes the effects of local linear growth and damping, spatially local nonlinear coupling to dissipation and spatial scattering of turbulence energy induced by nonlinear coupling. In the absence of dissipation, the front propagation into the linearly stable zone occurs with the property of rapid progression at small t, followed by slower subdiffusive progression at late times. The turbulence radial spreading into the linearly stable zone reduces the turbulent intensity in the linearly unstable zone, and introduces an additional dependence on the rho* is always equal to rho i/a to the turbulent intensity and the transport scaling. These are in broad, semi-quantitative agreements with a number of global gyrokinetic simulation results with zonal flows and without zonal flows. The front propagation stops when the radial flux of fluctuation energy from the linearly unstable region is balanced by local dissipation in the linearly stable region.},
doi = {10.2172/820109},
url = {https://www.osti.gov/biblio/820109}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Oct 20 00:00:00 EDT 2003},
month = {Mon Oct 20 00:00:00 EDT 2003}
}