title: Lagrangian frequency spectrum as a diagnostic for magnetohydrodynamic turbulence dynamics.
abstract: For the phenomenological description of magnetohydrodynamic turbulence competing models exist, e.g., Boldyrev [Phys. Rev. Lett. 96, 115002 (2006)] and Gogoberidze [Phys. Plasmas 14, 022304 (2007)], which predict the same Eulerian inertial-range scaling of the turbulent energy spectrum although they employ fundamentally different basic interaction mechanisms. A relation is found that links the Lagrangian frequency spectrum with the autocorrelation time scale of the turbulent fluctuations τ(ac) and the associated cascade time scale τ(cas). Thus, the Lagrangian energy spectrum can serve to identify weak (τ(ac) ≪ τ(cas)) and strong (τ(ac) ∼ τ(cas)) interaction mechanisms providing insight into the turbulent energy cascade. The new approach is illustrated by results from direct numerical simulations of two- and three-dimensional incompressible MHD turbulence.
authors.affiliation: Max-Planck-Institut für Plasmaphysik, Boltzmannstraße 2, 85748 Garching bei München, Germany. angela.busse@ipp.mpg.de
authors.forename: Angela
authors.initials: A
authors.lastname: Busse
authors.forename: Wolf-Christian
authors.initials: WC
authors.lastname: Müller
authors.forename: Grigol
authors.initials: G
authors.lastname: Gogoberidze