Speaker: Fábio Cruz (GoLP, Instituto Superior Técnico)
Title: First-principles kinetic simulations of pulsar magnetospheres
Abstract:
Pulsars gather a wealth of extreme physical conditions, making them unique environments where general relativity, quantum electrodynamics, and plasma physics meet. The electron-positron plasma that partially fills the pulsar magnetosphere is thought to be created via strong Quantum Electrodynamics (QED) cascades. In each step of this positive feedback process, electrons and positrons accelerated to TeV energies emit gamma-rays that, in the presence of 10^12 Gauss magnetic fields, decay into new electron-positron pairs. In this talk, I will present two classes of fully kinetic particle-in-cell simulations of pulsar magnetospheres. First, I will show local simulations including the QED processes relevant in pulsars from first principles, and show that plasma waves triggered by QED cascades can produce coherent electromagnetic waves, that are strong candidates for the longstanding problem of pulsar radio emission. Second, I will present global simulations, that demonstrate that QED cascades operating up to only a few stellar radii above the central neutron star can provide enough plasma to fill the whole pulsar magnetosphere and trigger dissipation at large radii, consistently with observations. Preliminary results of simulations of pulsars where general relativity is taken into account will be presented, and its role in the global dynamics of the magnetosphere will be discussed.
Room: ZOOM videoconference (contact justin.feng@tecnico.ulisboa.pt for URL)