Astroparticle Physics Theory

Very energetic particles known as cosmic rays (CRs) are intensively studied in modern high-energy astrophysics. Our group focuses its activity on the theoretical description of physical systems in which particle acceleration is known to occur, for example Supernova Remnants (SNRs), Active Galactic Nuclei (AGN), etc. Specifically, we are interested in both the micro- and macro-physics of these systems.

Directly ahead of SNR shocks one expects that cosmic rays drift relative to the ionized interstellar gas, which is an unstable situation. Plasma turbulence at collision-less shocks has very small wavelength scales and cannot be realistically described with MHD methods. We conduct intensive kinetic Particle-in-Cell (PIC) simulations in which we follow individual particles as they move in electric and magnetic fields. We thus explore the properties of magnetic turbulence near the shocks of SNRs and their role in the acceleration of energetic particles.

Additionally, we build global models of SNRs based on a semi-analytic description of the plasma flow behind the shock. Such an analytic study is a very fast and efficient tool for tracing the global behavior of the system. We are thus able to obtain the global parameters of the system and complement our numerical studies. Having established the parameters of the system, we calculate the expected emission in a wide spectral domain and compare our predictions with current experimental data.