Séminaire IPAG

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Magnetic Reconnection in High-Energy Astrophysics with Specific Applications to Blazar Jets

jeudi 17 février 2022 - 11h00

John Mehlhaff - IPAG
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The collisionless plasmas that accrete onto, and are launched from, neutron stars and black holes are a prominent source of emission detected from these fascinating objects. In these highly magnetized plasmas, a key process that likely shapes the emitted light is magnetic reconnection, which can liberate the energy stored in the strong magnetic field, delivering it to particles that then produce the observed radiation. Because the host plasma is often collisionless, studying magnetic reconnection in these contexts requires a kinetic (as opposed to a fluid, e.g., magnetohydrodynamic) description, and, for this task, the particle-in-cell (PIC) computational method provides a well-suited tool. In this talk, I cover (and hopefully demystify) practical aspects of applying the fundamental kinetic physics of reconnection, including deploying the PIC method, to high-energy astrophysical environments. I specialize to jets launched by active galactic nuclei and observed head-on as blazars, discussing specific connections between the physics of magnetic reconnection---including how it can serve as a relativistic particle accelerator, and how strong radiative losses and QED effects may modify the plasma-physical dynamics---and gamma-ray observations of these objects.

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Hôtes : Benoît Cerutti

Salle Manuel Forestini, 414 rue de la piscine, 38400 Saint Martin d'Hères