Date:
Tue, 01/03/202212:30-13:30
Title: Zooming-in on the microphysics of gamma-ray burst afterglows
Abstract: It is generally understood -- most notably so at HUJI! -- that the afterglow of gamma-ray bursts corresponds to synchrotron and inverse Compton radiation of electrons that have been accelerated at an ultra-relativistic shock wave traveling through the circumburst medium. What may be less appreciated, is that those electrons are accelerated via their interaction with a microturbulence that they themselves generate by beam-plasma instabilities, and that the physics of acceleration is intimately related to the microphysics of the relativistic, collisionless shock itself. This presentation proposes to zoom in on the kinetic scales of those shock fronts. In particular, it will introduce a recent theoretical model for weakly magnetized, relativistic collisionless shocks, which we have corroborated using large-scale particle-in-cell simulations. It will also address the origin of strong electron heating in the shock precursor.
Abstract: It is generally understood -- most notably so at HUJI! -- that the afterglow of gamma-ray bursts corresponds to synchrotron and inverse Compton radiation of electrons that have been accelerated at an ultra-relativistic shock wave traveling through the circumburst medium. What may be less appreciated, is that those electrons are accelerated via their interaction with a microturbulence that they themselves generate by beam-plasma instabilities, and that the physics of acceleration is intimately related to the microphysics of the relativistic, collisionless shock itself. This presentation proposes to zoom in on the kinetic scales of those shock fronts. In particular, it will introduce a recent theoretical model for weakly magnetized, relativistic collisionless shocks, which we have corroborated using large-scale particle-in-cell simulations. It will also address the origin of strong electron heating in the shock precursor.