Self-Similar Energy Decay in Magnetohydrodynamic Turbulence

Abstract

The self-similar decay of energy in magnetohydrodynamic flows is examined in the spirit of the Kolmogorov phenomenology while incorporating in the expression for the energy transfer to small scales the interactions between turbulent eddies and Alfvén waves due to a large-scale magnetic field. The model is parameter-free and does not rely on the existence of the several invariants of ideal MHD except energy. High-resolution numerical simulations in two dimensions confirm its validity in a way that leads as expected to a decay significantly slower than for neutral fluids.