KUL/CmPA Seminar: Interplay between kinetic plasma physics and radiative effects in sources of high-energy emission

Seminar by Dr. Daniel Groselj (Columbia University)

Title: Interplay between kinetic plasma physics and radiative effects in sources of high-energy emission


High-energy radiation from astrophysical sources is produced in a hot plasma that shines through emission from relativistic charged particles. The energization of particles is mediated by plasma processes, such as kinetic turbulence or collisionless shocks, that convert energy stored in magnetic fields and bulk flows into heat and non-thermal particles. This can be studied using kinetic particle-in-cell (PIC) simulations, which capture the first-principles interaction between particles and their self-consistent fields. Yet, in high-energy sources one generally also needs to consider the effects of intense radiation on the plasma dynamics, which can alter the particle energetics through radiative cooling and their composition via production of electron-positron pairs. Here, I will present results of recent PIC simulations and demonstrate some consequences of the interplay between radiative effects and plasma physics based on two examples: (1) collisionless gamma-ray burst (GRB) afterglow shocks enriched with electron-positron pairs, and (2) radiative kinetic turbulence in coronae of accreting black holes. I will comment on the astrophysical implications of these first-principles simulations for models of early GRB afterglows and for models of the hard state in X-ray binaries.

Where: The seminar can be followed in person in building 200B, room 01.14 or online at the following link:​


Friday, May 5, 2023 - 15:30 to 16:30

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