February 12, 2025 | 11 a.m. PT

Tristan Bachmann
Graduate Student, University of Rochester

Talk Title: Laboratory Exploration of Early Universe Magnetogenesis via the Biermann Battery Effect

Abstract: Magnetic fields are pervasive on cosmological and galactic scales, and understanding their formation and evolution is essential to our broad understanding of modern cosmology. One of the predominant proposed mechanisms for the origin of these fields is via the Biermann battery effect, which describes the spontaneous generation of magnetic fields due to non-parallel density and temperature gradients in plasmas. Though the effect is difficult to observe directly in the intergalactic medium, we use scaling relations to investigate these phenomena on laboratory scales. Using the FLASH MHD code, we collaborate with experimentalists at UCLA to model the generation of Biermann-driven fields in such a laboratory setting, using high repetition rate laser produced plasmas at a frequency of ~1 Hz. We validate the FLASH code in new spatiotemporal regimes, and we use these newly validated capabilities to assist in the modeling and design of ongoing laboratory astrophysics experiments. We also perform large scale simulations to investigate the generation and subsequent amplification of seed fields and their impact on large scale structure.

Bio: Tristan is a 3rd year Ph.D. student at the University of Rochester, working in the Flash Center for Computational Science with Professor Petros Tzeferacos. Their background is in computational and observational cosmology, having worked with the Dark Energy Survey for their undergraduate research. They are interested in computational astrophysics, especially as a means of bridging the gap between laboratory astrophysics experiments and observational astronomy. They are particularly interested in magnetized systems, including accretion and jet launching systems, cosmic magnetogenesis, and magnetized collisionless shocks in astrophysical systems.