Turbulence spreading and transport scaling in global gyrokinetic particle simulations
- 1 March 2004
- journal article
- research article
- Published by AIP Publishing in Physics of Plasmas
- Vol. 11 (3), 1099-1108
- https://doi.org/10.1063/1.1647136
Abstract
An intriguing observation in magnetically confined plasma experiments and in global gyrokinetic particle simulations of toroidal ion temperature gradient turbulence is that the fluctuations are microscopic, while the resulting turbulent transport is not gyro-Bohm [Z. Lin et al., Phys. Rev. Lett. 88, 195004 (2002)]. A possible resolution to this puzzle is identified as turbulence spreading from the linearly active (unstable) region to the linearly inactive (stable) region. Large scale gyrokinetic simulations found that transport driven by microscopic fluctuations is diffusive and local, whereas the fluctuation intensity is determined by nonlocal effects. Fluctuations are found to spread from the linearly active region to the linearly inactive region. This turbulence spreading reduces the fluctuation intensity in the unstable region, especially for a smaller device size, and thus introduces a nonlocal dependence in the fluctuation intensity. The device size dependence of the fluctuation intensity, in turn, is responsible for the observed gradual transition from Bohm to gyro-Bohm transport scaling.Keywords
This publication has 38 references indexed in Scilit:
- Non-perturbative models of intermittency in drift-wave turbulence: towards a probabilistic theory of anomalous transportNuclear Fusion, 2003
- Global gyrokinetic simulation of ion temperature gradient driven turbulence in plasmas using a canonical Maxwellian distributionNuclear Fusion, 2003
- Energy conservation in a nonlinear gyrokinetic particle-in-cell code for ion-temperature-gradient-driven modes in θ-pinch geometryPhysics of Plasmas, 2002
- Non-dimensional scaling of turbulence characteristics and turbulent diffusivityNuclear Fusion, 2001
- Gyrokinetic simulations in general geometry and applications to collisional damping of zonal flowsPhysics of Plasmas, 2000
- Effects of Collisional Zonal Flow Damping on Turbulent TransportPhysical Review Letters, 1999
- Flux driven turbulence in tokamaksNuclear Fusion, 1999
- Fluctuation-induced heat transport results from a large global 3D toroidal particle simulation modelPlasma Physics and Controlled Fusion, 1996
- Radial propagation of turbulence in tokamaksNuclear Fusion, 1994
- Scaling laws for plasma confinementNuclear Fusion, 1977