Shining Black Holes: Magnetic Field Generation and Relevant Plasma Structures. Emergence of Spin in the Universe

Non-thermal particle populations are a realistic feature of the radiation emitting plasmas associated with black holes.  Representing this feature by a non-isotropic plasma pressure, macroscopic processes driven by it in combinations with gravity and differential rotation have been found.  One class of these is that of magneto-gravitational modes identified originally for plasmas with isotropic thermal particle distributions in momentum space that can emerge for currentless plasma disks. These “anisotropy” modes can lead to new equilibrium configurations, such as solitary rings or ring sequences, and to strong amplification of a seed magnetic field and can be axisymmetric or of the trailing spiral type.  In the last case they lend themselves to explain the presence of Quasi Periodic Oscillations (QPO’s) in the emission spectra from black holes corresponding to the local frequencies of Keplerian particle orbits.  The new equilibrium configurations that are found to be associated with a non-isotropic particle pressures do not require a seed magnetic field for their existence and involve magnetic energy densities that can be of the order of the particle thermal energy densities.  Then a theoretically well founded process for generation of magnetic fields in the Universe can be envisioned.  

An important related issue is that of the transport (e.g. local emergence) of angular momentum in the Universe. The spontaneous rotation phenomenon observed in axisymmetric laboratory plasmas has provided the incentive to identify collective modes that can extract angular momentum from one region and concentrate it in another.  The widely used concept of viscosity to describe the transport of angular momentum is shown to be inadequate in this context.