Uploaded June 2025 | Updated September 2026, 3 weeks ago

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Speaker : Dr. Jennifer Schober (Bonn)
Date : 17th June 2025
Title : The magnetic history of the Universe
Abstract : Magnetic fields permeate nearly every astrophysical
environment, from planets and stars to galaxies and galaxy clusters. In
these cosmologically overdense regions, magnetic fields are thought to
arise primarily from magnetohydrodynamic (MHD) dynamos. These mechanisms
convert turbulent kinetic energy into magnetic energy through the
stretching and twisting of field lines. In the first part of this talk,
I will present recent advances in our understanding of MHD dynamos. In
the second part, I will focus on the vast underdense regions of space,
cosmic voids, where blazar observations have revealed the existence of
magnetic fields. As voids lack turbulence and therefore the energy
source of classical dynamos, these large-scale magnetic fields likely
originate in the very early Universe shortly after the Big Bang and
therefore offer a unique window into fundamental physics. I will outline
key theoretical models of magnetogenesis and present new insights in the
pre-recombination evolution of these primordial magnetic fields from
state-of-the-art numerical simulations.