CCA Colloquium: Andrei Beloborodov

Title: Magnetic power in the universe of bright transients

Abstract:
Sudden release of magnetic energy is a prominent phenomenon in time-domain astrophysics. It is invoked in a variety of powerful fast transients, including magnetar X-ray flares, cosmological fast radio bursts, neutron star mergers and gamma-ray bursts. Magnetic energy is dissipated by electric fields which can break ideal MHD and energize plasma particles. Such dissipative fields develop on microscopic scales in turbulence cascades and in magnetic reconnection. Significant computational efforts are currently invested to understand the energy release process from first principles, using kinetic plasma simulations. Magnetic flares around compact objects occur in a dense radiation field, which changes the dissipation mechanism. Powerful magnetic flares create opaque electron-positron plasma and launch blast waves. The accompanying radiative processes shape the observed bursts.

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