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Updated: May 14, 2026
06:42
Magnetically Induced Rotating Rayleigh-Taylor Instability
Published on: March 3, 2017
Cosmic magnetization: from spontaneously emitted aperiodic turbulent to ordered equipartition fields
1Institut für Theoretische Physik, Lehrstuhl IV: Weltraum- und Astrophysik, Ruhr-Universität Bochum, D-44780 Bochum, Germany. rsch@tp4.rub.de
Physical Review Letters
|February 2, 2013
Summary
An unmagnetized plasma spontaneously generates weak, aperiodic magnetic field fluctuations. These turbulent fields, though initially weak in the intergalactic medium, can be amplified by cosmic events like supernova explosions.
Area of Science:
- Plasma Physics
- Astrophysics
- Cosmic Magnetic Fields
Background:
- The origin and evolution of magnetic fields in the early universe are not fully understood.
- Previous models have not fully explained the spontaneous generation of magnetic fields in unmagnetized plasmas.
- The intergalactic medium (IGM) and protogalaxies are key environments for studying early cosmic magnetic fields.
Purpose of the Study:
- To investigate the spontaneous emission of magnetic field fluctuations in unmagnetized nonrelativistic thermal electron-proton plasmas.
- To estimate the strength of these magnetic fields in the early universe, specifically in cosmic voids and protogalaxies.
- To determine the impact of viscous damping and amplification mechanisms on these seed magnetic fields.
Main Methods:
- Theoretical analysis of spontaneous magnetic field generation in plasmas.
- Calculation of magnetic field strength using plasma parameters: normalized thermal electron temperature (βe), thermal plasma energy density (We), and plasma parameter (g).
- Inclusion of viscous damping effects and amplification by supernova-induced shear and compression.
Main Results:
- Unmagnetized plasmas spontaneously emit aperiodic turbulent magnetic field fluctuations.
- Estimated field strengths in the early IGM are ~2×10⁻¹⁶ G in voids and ~2×10⁻¹⁰ G in protogalaxies.
- Viscous damping reduces these to ~2×10⁻²¹ G in voids and ~2×10⁻¹² G in protogalaxies, with subsequent amplification possible.
Conclusions:
- The proposed mechanism generates weak seed magnetic fields in the early universe.
- These fields are initially too weak to influence plasma dynamics but can be amplified.
- Supernova explosions can locally amplify these fields, leading to anisotropic magnetic structures that eventually influence gas dynamics.
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