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titolo
Avviso di Seminario
target
totem,dipartimento,ppim
inizio
Lunedì 27 Gennaio 2020 ore 11:00
luogo
Sala riunioni 3o piano edificio di via Pascoli
relatore
Vincenzo Antonuccio Inaf - Catania Astrophysical Observatory
titoloevento
Magnetohydrodynamic simulations of relativistic jets: The emergence of backflows
abstract
The circulation within AGN jets is characterized by the presence of counter-streaming flows which usually
originate near the tip of the jet itself, and propagate towards the central regions. These backflows are
observed both in high-resolution numerical simulations and in nearby optical and radio polarization maps
of AGN (non-blazar) jets. We show that their physical origin can be traced to a fluid dynamical mechanism:
the presence of (classical and relativistic) enthalpy gradients, through the Crocco or Carter-Lichnerowicz
theorem (for the newtonian and relativistic versions, respectively), even for laminar flows. Numerical
experiments using AMR codes (FLASH 4.6) confirm quantitatively these theoretical models during the early
linear stages of jet propagation. These backflows persist after the linear phase: we will demonstrate that
they convey hot, high-pressure gas which can interact with the central accretion disc's corona and heavily
affect the mechanism underlying the jet's production mechanism.
organizzatori
Istituto Nazionale di Fisica Nucleare Sezione di Perugia