Séminaire IPAG

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Extreme Plasma Astrophysics

jeudi 14 novembre 2024 - 11h00

Dmitri Uzdensky - Oxford University
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Recent years have presented us with an endless stream of spectacular observational discoveries in high-energy and multi-messenger astrophysics of relativistic compact objects --- neutron stars and black holes. Real breakthroughs like the discovery of gravitational waves from merging black holes and neutrons stars, Fast Radio Bursts (FRBs) and their association with magnetars, and unprecedented event-horizon-scale images of accreting black holes, as well as many others, create a sense of great excitement in the field. Most of the observational information about these sources comes to us as electromagnetic radiation emitted by the plasma around these exotic objects; thus, understanding the underlying plasma physics is crucial to interpreting these observed phenomena. Importantly, however, the basic physics of these extreme plasma environments differs drastically from traditional plasma physics applicable to space, solar, and laboratory plasmas — it is enriched by a plethora of relativistic (both special and general), radiation-reaction, and quantum-electrodynamics (QED) (e.g. pair production) effects. Understanding how these effects modify key collective plasma processes like waves, instabilities, turbulence, shocks, magnetic reconnection, is the scope of Extreme Plasma Astrophysics. I will review the great ongoing progress in exploring this exciting new frontier, enabled by the advent of innovative advanced radiative kinetic plasma simulation codes and strongly motivated by observational discoveries. I will especially highlight recent breakthroughs in our understanding of radiative plasma turbulence and magnetic reconnection, with applications to accreting black holes and neutron stars. I will also outline the key theoretical challenges and future prospects of Extreme Plasma Astrophysics.

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