CAREER: Magnetogenesis and Plasma Dynamo Across Cosmic Time

Princeton University, Princeton NJ

Investigators

Abstract

Magnetic fields are now routinely measured both in our Galaxy and in clusters of galaxies. The investigator seeks to understand the origin of these fields, focusing on the complex changes of the magnetic fields over long periods of time. They address these questions: Why is the nearby Universe magnetized at the observed levels? When were these fields produced? More specifically, what material properties give the galaxy-forming material the ability to grow and sustain strong magnetic fields? The investigator plans traditional, paper and pencil, calculations combined with state-of-the-art supercomputer simulations to better understand how these magnetic fields came to be. Predictions for the strength and structure of magnetic fields in protogalaxies and intergalactic space will be made in preparation for next-generation radio telescopes. The investigator plans to provide women and underrepresented groups the training and encouragement to choose a career in astrophysical fluid dynamics or plasma astrophysics. These goals are in response to the alarming dearth of women and minorities in plasma science and the relative lack of fluid and plasma education in U.S. physics and astronomy curricula. A program of biennial summer schools, targeting members of these groups, will be initiated. All materials from the schools will be made publicly available, and a study will track the impact of these schools on recruitment and retention in the field. The investigator will describe, from first principles, the creation and development of cosmic magnetism and dynamo across time, focusing specifically on the amplification of pre-existing seed magnetic fields in protogalaxies and in clusters of galaxies by instabilities, turbulence, and large-scale shear. The investigator will determine how the material properties of a plasma influence its ability to grow and sustain dynamically important magnetic fields. They will model the properties change with time, from the epoch of re-ionization to the early lives of galaxies. Answering these questions is complicated by the low densities and high temperatures in these systems, which precludes a magneto-hydrodynamic description and brings microphysical plasma processes to the fore. Their pioneering work on the dynamo in this regime is leveraged to argue for a phase of explosive field growth in the early development of protogalaxies and the intra-galactic cluster medium. They formulate a research plan to investigate this possibility by combining traditional analytical techniques with state-of-the-art numerical tools. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.