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Title: Gyrokinetic Studies of Turbulence in Steep Gradient Region: Role of Turbulence Spreading and E x B Shear

Abstract

An integrated program of gyrokinetic particle simulation and theory has been developed to investigate several outstanding issues in both turbulence and neoclassical physics. Gyrokinetic particle simulations of toroidal ion temperature gradient (ITG) turbulence spreading using the GTC code and its related dynamical model have been extended to the case with radially increasing ion temperature gradient, to study the inward spreading of edge turbulence toward the core. Due to turbulence spreading from the edge, the turbulence intensity in the core region is significantly enhanced over the value obtained from simulations of the core region only. Even when the core gradient is within the Dimits shift regime (i.e., self-generated zonal flows reduce the transport to a negligible value), a significant level of turbulence and transport is observed in the core due to spreading from the edge. The scaling of the turbulent front propagation speed is closer to the prediction from our nonlinear diffusion model than one based on linear toroidal coupling. A calculation of ion poloidal rotation in the presence of sharp density and toroidal angular rotation frequency gradients from the GTC-Neo particle simulation code shows that the results are significantly different from the conventional neoclassical theory predictions. An energy conserving setmore » of a fully electromagnetic nonlinear gyrokinetic Vlasov equation and Maxwell's equations, which is applicable to edge turbulence, is being derived via the phase-space action variational Lie perturbation method. Our generalized ordering takes the ion poloidal gyroradius to be on the order of the radial electric field gradient length.« less

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Princeton Plasma Physics Lab., Princeton, NJ (US)
Sponsoring Org.:
USDOE Office of Science (SC) (US)
OSTI Identifier:
836572
Report Number(s):
PPPL-4037
TRN: US0500637
DOE Contract Number:
AC02-76CH03073
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 21 Dec 2004
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; BOLTZMANN-VLASOV EQUATION; DIFFUSION; ELECTRIC FIELDS; FORECASTING; ION TEMPERATURE; PHASE SPACE; PHYSICS; ROTATION; SHEAR; SIMULATION; TRANSPORT; TURBULENCE; VELOCITY; GYROKINETIC EQUATIONS; H-MODE PLASMA CONFINEMENT

Citation Formats

T.S. Hahm, Z. Lin, P.H. Diamond, G. Rewoldt, W.X. Wang, S. Ethier, O. Gurcan, W.W. Lee, and W.M. Tang. Gyrokinetic Studies of Turbulence in Steep Gradient Region: Role of Turbulence Spreading and E x B Shear. United States: N. p., 2004. Web. doi:10.2172/836572.
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T.S. Hahm, Z. Lin, P.H. Diamond, G. Rewoldt, W.X. Wang, S. Ethier, O. Gurcan, W.W. Lee, & W.M. Tang. Gyrokinetic Studies of Turbulence in Steep Gradient Region: Role of Turbulence Spreading and E x B Shear. United States. doi:10.2172/836572.
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T.S. Hahm, Z. Lin, P.H. Diamond, G. Rewoldt, W.X. Wang, S. Ethier, O. Gurcan, W.W. Lee, and W.M. Tang. Tue . "Gyrokinetic Studies of Turbulence in Steep Gradient Region: Role of Turbulence Spreading and E x B Shear". United States. doi:10.2172/836572. https://www.osti.gov/servlets/purl/836572.
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@article{osti_836572,
title = {Gyrokinetic Studies of Turbulence in Steep Gradient Region: Role of Turbulence Spreading and E x B Shear},
author = {T.S. Hahm and Z. Lin and P.H. Diamond and G. Rewoldt and W.X. Wang and S. Ethier and O. Gurcan and W.W. Lee and W.M. Tang},
abstractNote = {An integrated program of gyrokinetic particle simulation and theory has been developed to investigate several outstanding issues in both turbulence and neoclassical physics. Gyrokinetic particle simulations of toroidal ion temperature gradient (ITG) turbulence spreading using the GTC code and its related dynamical model have been extended to the case with radially increasing ion temperature gradient, to study the inward spreading of edge turbulence toward the core. Due to turbulence spreading from the edge, the turbulence intensity in the core region is significantly enhanced over the value obtained from simulations of the core region only. Even when the core gradient is within the Dimits shift regime (i.e., self-generated zonal flows reduce the transport to a negligible value), a significant level of turbulence and transport is observed in the core due to spreading from the edge. The scaling of the turbulent front propagation speed is closer to the prediction from our nonlinear diffusion model than one based on linear toroidal coupling. A calculation of ion poloidal rotation in the presence of sharp density and toroidal angular rotation frequency gradients from the GTC-Neo particle simulation code shows that the results are significantly different from the conventional neoclassical theory predictions. An energy conserving set of a fully electromagnetic nonlinear gyrokinetic Vlasov equation and Maxwell's equations, which is applicable to edge turbulence, is being derived via the phase-space action variational Lie perturbation method. Our generalized ordering takes the ion poloidal gyroradius to be on the order of the radial electric field gradient length.},
doi = {10.2172/836572},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Dec 21 00:00:00 EST 2004},
month = {Tue Dec 21 00:00:00 EST 2004}
}
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Technical Report:
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DOI:  10.2172/836572
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