Reynolds numbers in the early Universe
arXiv:1111.3867 · doi:10.1016/j.physletb.2012.04.007
Abstract
After electron-positron annihilation and prior to photon decoupling the magnetic Reynolds number is approximately twenty orders of magnitude larger than its kinetic counterpart which is, in turn, smaller than one. In this globally neutral system the large-scale inhomogeneities are provided by the spatial fluctuations of the scalar curvature. Owing to the analogy with the description of Markovian conducting fluids in the presence of acoustic fluctuations, the evolution equations of a putative magnetic field are averaged over the large-scale flow determined by curvature perturbations. General lessons are drawn on the typical diffusion scale of magnetic inhomogeneities. It is speculated that Reynolds numbers prior to electron-positron annihilation can be related to the entropy contained in the Hubble volume during the various stages of the evolution of the conducting plasma.
9 pages, 2 figures
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- Compressible hydromagnetic nonlinearities in the predecoupling plasma
- Primordial Magnetic Helicity from Stochastic Electric Currents
- Cosmological Ohm's law and dynamics of non-minimal electromagnetism
- Primordial Black Holes Formed during Magneto-Hydrodynamic Turbulence in The Early Universe as Dominant Part of Dark Matter
- Extrapolation of Turbulence Intensity Scaling to