title: Critical behavior in the inverse to forward energy transition in two-dimensional magnetohydrodynamic flow.
abstract: We investigate the critical transition from an inverse cascade of energy to a forward energy cascade in a two-dimensional magnetohydrodynamic flow as the ratio of magnetic to mechanical forcing amplitude is varied. It is found that the critical transition is the result of two competing processes. The first process is due to hydrodynamic interactions and cascades the energy to the large scales. The second process couples small-scale magnetic fields to large-scale flows, transferring the energy back to the small scales via a nonlocal mechanism. At marginality the two cascades are both present and cancel each other. The phase space diagram of the transition is sketched.
authors: Laboratoire de Physique Statistique, École Normale Supérieure, CNRS UMR 8550, Université Paris Diderot, Université Pierre et Marie Curie, 24 rue Lhomond, 75005 Paris, France.
authors: Kannabiran
authors: K
authors: Seshasayanan
authors: Laboratoire de Physique Statistique, École Normale Supérieure, CNRS UMR 8550, Université Paris Diderot, Université Pierre et Marie Curie, 24 rue Lhomond, 75005 Paris, France.
authors: Alexandros
authors: A
authors: Alexakis