title: Free energy cascade in gyrokinetic turbulence.
abstract: In gyrokinetic theory, the quadratic nonlinearity is known to play an important role in the dynamics by redistributing (in a conservative fashion) the free energy between the various active scales. In the present study, the free energy transfer is analyzed for the case of ion temperature gradient driven turbulence. It is shown that it shares many properties with the energy transfer in fluid turbulence. In particular, one finds a (strongly) local, forward (from large to small scales) cascade of free energy in the plane perpendicular to the background magnetic field. These findings shed light on some fundamental properties of plasma turbulence, and encourage the development of large-eddy-simulation techniques for gyrokinetics.
authors.affiliation: Université Libre de Bruxelles, Faculté des Sciences, Physique Statistique et Plasmas CP 231, EURATOM Association, Campus Plaine, 1050 Brussels, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Bañón Navarro
authors.forename: P
authors.initials: P
authors.lastname: Morel
authors.forename: M
authors.initials: M
authors.lastname: Albrecht-Marc
authors.forename: D
authors.initials: D
authors.lastname: Carati
authors.forename: F
authors.initials: F
authors.lastname: Merz
authors.forename: T
authors.initials: T
authors.lastname: Görler
authors.forename: F
authors.initials: F
authors.lastname: Jenko