2014/07/31 by Jonathan Zrake · 3 citations
Physics and Astronomy · #Afterglow #Astrophysics #Astrophysics and Cosmic Phenomena #Cascade #Computational physics #Explosive material #Gamma-ray burst #Gamma-ray bursts and supernovae #Magnetic energy #Magnetic field #Magnetic reconnection #Magnetization #Magnetohydrodynamic drive #Magnetohydrodynamic turbulence #Magnetohydrodynamics #Mechanics #Physics #Quantum mechanics #Solar and Space Plasma Dynamics #Turbulence #astro-ph.HE
paper · pdf · doi:10.1088/2041-8205/794/2/l26
Accepted to ApJ Letters
arxiv created 2014/09/30 · openalex publication_date 2014/10/08 · arxiv updated 2015/06/22 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The free decay of nonhelical relativistic magnetohydrodynamic turbulence is studied numerically, and found to exhibit cascading of magnetic energy toward large scales. Evolution of the magnetic energy spectrum P M ( k , t ) is self-similar in time and well modeled by a broken power law with subinertial and inertial range indices very close to 7/2 and −2, respectively. The magnetic coherence scale is found to grow in time as t 2/5 , much too slow to account for optical polarization of gamma-ray burst afterglow emission if magnetic energy is to be supplied only at microphysical length scales. No bursty or explosive energy loss is observed in relativistic MHD turbulence having modest magnetization, which constrains magnetic reconnection models for rapid time variability of GRB prompt emission, blazars, and the Crab nebula.