Excitation of geodesic acoustic mode continuum by drift wave turbulence

2012 ◽  
Vol 78 (6) ◽  
pp. 651-655 ◽  
Author(s):  
JUN YU ◽  
J. Q. DONG ◽  
X. X. LI ◽  
D. DU ◽  
X. Y. GONG
Keyword(s):  
Growth Rate ◽  
Acoustic Mode ◽  
Kinetic Approach ◽  
Wave Turbulence ◽  
Ion Temperature ◽  
Drift Wave Turbulence ◽  
Acoustic Modes ◽  
Drift Wave ◽  
Radial Structure ◽  
Geodesic Acoustic Mode

AbstractExcitation of the geodesic acoustic mode continuum by drift wave turbulence is studied using the wave kinetic approach. For a model profile of weak non-uniform ion temperature, the forms of growth rate and radial structure of geodesic acoustic modes are obtained analytically. The growth rate is analyzed for several conditions for present-day tokamaks and compared with that for uniform ion temperature, as well as that given by the coherent mode approach for non-uniform ion temperature.

scholarly journals Propagation direction of geodesic acoustic modes driven by drift wave turbulence

2018 ◽  
Vol 58 (11) ◽  
pp. 112005 ◽  
Author(s):  
M. Sasaki ◽  
K. Itoh ◽  
T. Kobayashi ◽  
N. Kasuya ◽  
A. Fujisawa ◽  
...  
Keyword(s):  
Propagation Direction ◽  
Wave Turbulence ◽  
Drift Wave Turbulence ◽  
Acoustic Modes ◽  
Drift Wave

scholarly journals Investigation of tokamak turbulent avalanches using wave-kinetic formulation in toroidal geometry

2021 ◽  
Vol 87 (2) ◽  
Author(s):  
Camille Gillot ◽  
Guilhem Dif-Pradalier ◽  
Xavier Garbet ◽  
Olivier Panico ◽  
Yanick Sarazin ◽  
...  
Keyword(s):  
Coupled System ◽  
Wave Turbulence ◽  
Ion Temperature ◽  
Flow Shear ◽  
Ion Temperature Gradient ◽  
Kinetic Formulation ◽  
Drift Wave Turbulence ◽  
Drift Wave ◽  
Low Field ◽  
Primary Driver

The interplay between toroidal drift-wave turbulence and tokamak profiles is investigated using a wave-kinetic description. The coupled system is used to investigate the interplay between marginally stable toroidal drift-wave turbulence and geodesic acoustic modes (GAMs). The coupled system is found to be unstable. Notably, the most unstable mode corresponds to the resonance between the turbulent wave radial group velocity and the GAM phase velocity. For a low-field-side ballooned drift-wave growth, a background flow shear breaks the symmetry between inwards- and outwards-travelling instabilities. Although this turbulence–GAM coupling may not be the primary driver for avalanches in standard core ion temperature gradient simulations, this mechanism is generic and displays many of the expected features, and should be of interest in several other regimes, which include towards the edge or in the presence of energetic particles.

Applications of the wave kinetic approach: From laser wakefields to drift wave turbulence

2009 ◽  
Vol 16 (5) ◽  
pp. 055904 ◽  
Author(s):  
R. M. G. M. Trines ◽  
R. Bingham ◽  
L. O. Silva ◽  
J. T. Mendonça ◽  
P. K. Shukla ◽  
...  
Keyword(s):  
Kinetic Approach ◽  
Wave Turbulence ◽  
Drift Wave Turbulence ◽  
Drift Wave

scholarly journals Soliton generation and drift wave turbulence spreading via geodesic acoustic mode excitation

2021 ◽  
Author(s):  
Ningfei Chen ◽  
Shizhao Wei ◽  
Guangyu Wei ◽  
Zhiyong Qiu
Keyword(s):  
Acoustic Mode ◽  
Stable Region ◽  
Field Equations ◽  
Fully Nonlinear ◽  
Distinctive Features ◽  
Drift Wave Turbulence ◽  
Nonlinear Growth ◽  
Drift Wave ◽  
Geodesic Acoustic Mode ◽  
Two Stages

Abstract The two-field equations governing fully nonlinear dynamics of the drift wave (DW) and geodesic acoustic mode (GAM) interaction in toroidal geometry are derived in the nonlinear gyrokinetic framework. Two stages with distinctive features are identified and analyzed by both analytical and numerical approaches. In the linear growth stage, the derived set of nonlinear equations can be reduced to the intensively studied parametric decay instability (PDI), accounting for the spontaneous resonant excitation of GAM by DW. The main results of previous works on spontaneous GAM excitation, e.g., the much enhanced GAM group velocity and the nonlinear growth rate of GAM, are reproduced from the numerical solution of the two-field equations. In the fully nonlinear stage, soliton structures are observed to form due to the balancing of the self-trapping effect by the spontaneously excited GAM and kinetic dispersiveness of DW. The soliton structures enhance turbulence spreading from DW linearly unstable to stable region, exhibiting convective propagation instead of typical linear dispersive process, and is thus, expected to induce core-edge interaction and nonlocal transport.

Theory of electric‐field curvature effects on long‐wavelength drift wave turbulence

1994 ◽  
Vol 1 (5) ◽  
pp. 1142-1153 ◽  
Author(s):  
K. L. Sidikman ◽  
B. A. Carreras ◽  
P. H. Diamond ◽  
L. Garcia
Keyword(s):  
Electric Field ◽  
Wave Turbulence ◽  
Long Wavelength ◽  
Drift Wave Turbulence ◽  
Curvature Effects ◽  
Drift Wave ◽  
Field Curvature
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