Oct 08, 2020

Mario Riquelme, University of Chile

"10/8/2020 Astronomy Colloquium - Mario Riquelme, University of Chile, " Particle acceleration by pressure anisotropy plasma instabilities: from black hole accretion disks to solar flares"."

Pressure anisotropies naturally arise in weakly collisional plasmas, and are ultimately limited by the pitch-angle scattering provided by various kinetic plasma instabilities. I will present particle-in-cell (PIC) plasma simulations of these instabilities, and will show that, in some regimes, their scattering can be highly inelastic and produce significant nonthermal particle acceleration. The presentation will focus on two astrophysical plasma environments: i) sub-relativistic, weakly collisional accretion disks around black holes (e.g., Sgr A*), where both electron and ion acceleration will be considered, and ii) non-relativistic, low beta plasmas relevant for solar flares, where the case of electron acceleration will be analyzed. I will review the main evidence for the existence of particle acceleration in these systems, and will discuss the importance that pressure anisotropy instabilities can have in helping explain these fascinating acceleration phenomena. 

Zoom Information


            Meeting ID: 885 1389 6776

            Passcode: 713070

Event Details

Oct 08, 2020



Tea at 3:30 pm Talk begins at 3:45 pm. See abstract for Zoom information.

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