Abstract
The possibility of generating diffuse radiation in extended astronomical media by plasma turbulence is investigated under the assumption that the turbulence can be understood as an ensemble of small-scale magnetic filaments (narrow current sheets) forming a texture around a large number of magnetic depletions or voids. On astronomically microscopic scales, the dilute high temperature medium (plasma) is to be considered ideally conducting, forming a collection of Josephson junctions between two such adjacent quasi-superconductors. The oscillation frequency of those junctions depends on the part of the spectrum that contributes to the oscillation, causing weak radio backgrounds. Lowest Josephson frequencies/energies near zero may become sources of quasi-stationary magnetic fields.
Highlights
Diffuse radiation from extended astrophysical objects like clusters of galaxies is conventionally attributed to synchrotron radiation [1, 2] from a distribution of relativistic particles which have been accelerated by some diffusive Fermi-like acceleration mechanism [cf., e.g., the monography 3] in the assumed always present magnetohydrodynamic plasma turbulence, both well-established, commonly accepted and successfully applied processes which provide valuable information about the physical state of the radiation sources, in particular the energy of the radiating particles and the strength of the scattering magnetic fields
The medium subject to this kind of turbulence consists of magnetic vortices, small-scale current sheets, and magnetic depletions separated on the larger scale by very narrow magnetic walls and filaments, which, in well-developed turbulence, may form more or less irregular chains of magnetic voids
Each individual junction consists of just two neighboring magnetic depletions, which are connected via the narrow separating magnetic wall or filament, structures of which belong to the turbulent texture that is generated in the volume by the free energy source of the turbulence: active galactic nuclei (AGNs), supernova remnants (SNRs), or any other object/process responsible for feeding turbulence such as collisionless shocks [4] and their environments [5, 6], the interstellar medium [7], or stellar winds, as shown by the example of the solar wind [8,9,10]
Summary
Diffuse radiation from extended astrophysical objects like clusters of galaxies is conventionally attributed to synchrotron radiation [1, 2] from a distribution of relativistic particles which have been accelerated by some diffusive Fermi-like acceleration mechanism [cf., e.g., the monography 3] in the assumed always present magnetohydrodynamic plasma turbulence, both well-established, commonly accepted and successfully applied processes which provide valuable information about the physical state of the radiation sources, in particular the energy of the radiating particles and the strength of the scattering magnetic fields. We propose a different mechanism, which in some cases may add to provide additional diagnostic information about turbulent emission sources It is not based on the assumption of an energetic particle distribution but restricts to the presence of turbulence in extended objects such as turbulent supernova remnants, galaxies, clusters of galaxies, and possibly even the cosmological large-scale structure of the Universe, which exhibits a particular texture consisting of filamented matter and voids. Each individual junction consists of just two neighboring magnetic depletions, which are connected via the narrow separating magnetic wall or filament, structures of which belong to the turbulent texture that is generated in the volume by the free energy source of the turbulence: active galactic nuclei (AGNs), supernova remnants (SNRs), or any other object/process responsible for feeding turbulence such as collisionless shocks [4] and their environments [5, 6], the interstellar medium [7], or stellar winds, as shown by the example of the solar wind [8,9,10]
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