Extreme Plasma Astrophysics | Prof. Dmitri Uzdensky

Date: 22 November, 2024
Speaker: Prof. Dmitri Uzdensky

Many spectacular phenomena in the high-energy Universe, such as bright and rapid gamma-ray flares, are powered by complex collective processes in plasmas around relativistic objects: neutron stars and black holes. While our understanding of such processes has benefitted greatly from the knowledge obtained in traditional (space, solar, laboratory) plasma research, the physical conditions near black holes and neutron stars are so extreme that conventional intuition often fails, and a richer physics framework is required. Extreme astrophysical plasmas are relativistic, interact strongly with radiation, and may be subject to QED (pair-production and ultra-strong magnetic-field) effects. Understanding how collective plasma processes, such as magnetic reconnection, waves, turbulence, operate in the presence of these “exotic-physics” effects is the main goal of Extreme Plasma Astrophysics. Rapid progress in exploring this exciting new frontier is now being made, stimulated by growing astrophysical motivation and enabled by vigorous, concerted theoretical efforts and by recent computational breakthroughs due to the advent of novel first-principles relativistic kinetic plasma codes that incorporate radiation and QED effects. Laser-plasma experiments will soon also contribute to this revolution. In this talk, I will review the recent advances in this burgeoning new field, focusing on theoretical and computational studies of relativistic radiative magnetic reconnection and turbulence and their astrophysical applications to neutron-star magnetospheres and black-hole coronae and jets. I will also outline key theoretical challenges and future directions of Extreme Plasma Astrophysics.