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Coherent structure phenomena in drift wave-zonal flow turbulence
1Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, S7N 5E2 Canada.
Physical Review Letters
|October 4, 2000
Summary
Zonal flows, plasma potential perturbations, can evolve into long-lived structures. These structures explain intermittency in drift-wave turbulence and reduced anomalous transport.
Area of Science:
- Plasma physics
- Fluid dynamics
- Nonlinear dynamics
Background:
- Zonal flows arise from drift-wave turbulence.
- They are azimuthally symmetric plasma potential perturbations.
- Reynolds stresses drive their generation.
Purpose of the Study:
- Investigate the nonlinear evolution of zonal flows.
- Identify the formation of coherent structures.
- Understand their role in drift-wave turbulence intermittency.
Main Methods:
- Analysis of nonlinear evolution.
- Identification of self-bound wave packets.
- Study of stationary shear layers.
Main Results:
- Zonal flows exhibit nonlinear evolution beyond initial growth.
- Long-lived coherent structures are formed.
- These structures are self-bound wave packets with stationary shear layers.
- Reduced anomalous transport regions are intermittently distributed.
Conclusions:
- Coherent zonal flow structures are key to understanding intermittency in drift-wave turbulence.
- These structures dynamically regulate anomalous transport.