Speaker
Lorenzo Sironi
Description
Collisionless relativistic shocks are widely invoked as the engines that generate high-energy particles and radiation in some of the most extreme astrophysical environments—most notably, in the late stages of gamma-ray bursts and in pulsar wind nebulae. I will present recent advances in our theoretical and computational understanding of these shocks, with an emphasis on the mechanisms by which they self-generate magnetic fields through the nonlinear feedback of accelerated particles on the background plasma. I will also discuss how these shocks can excite high-frequency electromagnetic waves that propagate upstream, modifying the pre-shock medium and potentially enabling particle acceleration and magnetic turbulence.