Cosmic Magnetism Across Scales and Epochs

by Dr Pallavi Bhat (ICTS)

Wednesday 3 Jun 2026, 16:00 → 18:00 Asia/Kolkata

AG66

From the early Universe to galaxies and accreting black holes, magnetic fields appear across a wide range of scales and epochs, yet their origin and evolution remain fundamental open questions. In this talk, I will discuss recent advances in our understanding of magnetic-field evolution in turbulent astrophysical plasmas. I will begin in the early Universe, where our work has uncovered the role of reconnection in the nonlinear evolution of primordial magnetic fields, leading to inverse transfer of magnetic energy. This can potentially explain the magnetic fields inferred in cosmic voids from gamma-ray observations.

I will then turn to gravitationally bound structures. During collapse, turbulent dynamos can amplify magnetic fields far more rapidly than in stationary systems. I will show how the evolving background flow associated with collapse accelerates dynamo action, potentially explaining the early emergence of strong magnetic fields in high-redshift galaxies.

Finally, I will discuss magnetic-field generation in accretion disks around compact objects. In these systems, turbulence driven by the magneto-rotational instability sustains dynamo action, producing magnetic fields that regulate angular-momentum transport and influence the launching and evolution of astrophysical jets. I will highlight recent efforts to understand how disk dynamos connect to the formation of some of the most energetic outflows observed in the Universe.