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Visually Based Characterization of the Incipient Particle Motion in Regular Substrates: From Laminar to Turbulent Conditions
Published on: February 22, 2018
Locality and universality in gyrokinetic turbulence
Bogdan Teaca1, Alejandro Bañón Navarro, Frank Jenko
1Ecole Polytechnique Fédérale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Association Euratom-Confédération Suisse, CH-1015 Lausanne, Switzerland. bogdan.teaca@epfl.ch
Physical Review Letters
|February 2, 2013
Summary
Investigating nonlinear interactions in gyrokinetic turbulence reveals that despite a local energy cascade, infrared interactions exhibit nonlocal behavior due to the system's dissipative nature.
Area of Science:
- Plasma physics
- Fluid dynamics
- Computational physics
Background:
- Gyrokinetic turbulence is crucial for understanding plasma behavior in fusion devices.
- The ion-temperature gradient instability is a primary driver of turbulence in such systems.
- Nonlinear interactions govern energy transfer across different scales in turbulent plasmas.
Purpose of the Study:
- To analyze the locality of energy flux in gyrokinetic turbulence.
- To investigate the nature of nonlinear interactions driven by the ion-temperature gradient instability.
- To determine if gyrokinetic turbulence exhibits universal dynamical regimes.
Main Methods:
- Direct numerical simulations in toroidal flux tube geometry.
- Analysis of free energy scale flux using Kraichnan's infrared (IR) and ultraviolet locality functions.
- Examination of scale separation in energetic interactions.
Main Results:
- A local energy cascade was observed in the simulations.
- Infrared interactions displayed a significantly nonlocal behavior.
- An asymptotic level for locality exponents, indicating a universal regime, was not recovered.
Conclusions:
- Gyrokinetic turbulence, driven by ITG instability, shows a complex interplay of local and nonlocal interactions.
- The dissipative nature of the system prevents a universal dynamical regime from emerging.
- Nonlocality in IR interactions is a key feature of this turbulent system, impacting energy transfer mechanisms.
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