2008/06/30 by A. A. Schekochihin, A A Schekochihin, S C Cowley +13 · 5 citations
Physics and Astronomy · #Cascade #Dissipation #Energy cascade #Entropy production #Gyrokinetics #Ionosphere and magnetosphere dynamics #Kinetic energy #Magnetic confinement fusion research #Microturbulence #Nonlinear system #Scaling #Solar and Space Plasma Dynamics #Turbulence #astro-ph #nlin.CD #physics.plasm-ph #physics.space-ph
paper · pdf · doi:10.1088/0741-3335/50/12/124024
published as Plasma Phys. Control. Fusion 50, 124024 (2008) · iop revtex style, 14 pages, 1 figure; submitted to PPCF; invited talk for EPS Conference on Plasma Physics, Crete, June 2008; Replaced to match published version
arxiv created 2008/11/04 · openalex publication_date 2008/11/04 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
This paper describes a conceptual framework for understanding kinetic plasma turbulence as a generalized form of energy cascade in phase space. It is emphasized that conversion of turbulent energy into thermodynamic heat is only achievable in the presence of some (however small) degree of collisionality. The smallness of the collision rate is compensated by the emergence of small-scale structure in the velocity space. For gyrokinetic turbulence, a nonlinear perpendicular phase mixing mechanism is identified and described as a turbulent cascade of entropy fluctuations simultaneously occurring at spatial scales smaller than the ion gyroscale and in velocity space. Scaling relations for the resulting fluctuation spectra are derived. An estimate for the collisional cutoff is provided. The importance of adequately modeling and resolving collisions in gyrokinetic simulations is biefly discussed, as well as the relevance of these results to understanding the dissipation-range turbulence in the solar wind and the electrostatic microturbulence in fusion plasmas.