title: Classes of Hydrodynamic and Magnetohydrodynamic Turbulent Decay.
abstract: We perform numerical simulations of decaying hydrodynamic and magnetohydrodynamic turbulence. We classify our time-dependent solutions by their evolutionary tracks in parametric plots between instantaneous scaling exponents. We find distinct classes of solutions evolving along specific trajectories toward points on a line of self-similar solutions. These trajectories are determined by the underlying physics governing individual cases, while the infrared slope of the initial conditions plays only a limited role. In the helical case, even for a scale-invariant initial spectrum (inversely proportional to wave number k), the solution evolves along the same trajectory as for a Batchelor spectrum (proportional to k^{4}).
authors.affiliation: Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80303, USA.|JILA and Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, Colorado 80303, USA.|Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, 10691 Stockholm, Sweden.|Department of Astronomy, AlbaNova University Center, Stockholm University, 10691 Stockholm, Sweden.
authors.forename: Axel
authors.initials: A
authors.lastname: Brandenburg
authors.affiliation: The McWilliams Center for Cosmology and Department of Physics, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, USA.|Department of Physics, Laurentian University, Ramsey Lake Road, Sudbury, ON P3E 2C, Canada.|Abastumani Astrophysical Observatory, Ilia State University, 3-5 Cholokashvili Ave, Tbilisi, GE-0194, Georgia.
authors.forename: Tina
authors.initials: T
authors.lastname: Kahniashvili