Accelerazione di particelle in zone di riconnessione magnetica relativistica

Active Galactic Nuclei, Neutron Stars and Nebulae are objects able to produce some of the most energetic phenomena in the universe. The spectral signature of these objects features highly non-thermal radiation mostly coming from synchrotron and inverse Compton processes by accelerated relativistic particles. Diffusive shock acceleration has been pointed out as respoinsible for particles acceleration in astrophysical sources. However, recent evidence showed that diffusive shock acceleration is inefficient in strongly magnetized and/or perpendicular shocks. On the other hand, magnetic reconnection, the topological rearrangment of magnetic field lines in a plasma, has been often invoked as more efficient and universal acceleration process. Here I present a new module of the PLUTO code which solves resistive relativistic magnetohydrodynamics equations with a new original algorithm in order to evolve the electric field, whose evolutionary equation is stiff. Furthermore, after some tests of the particle module of the PLUTO code, I present the first numerical simulations of test particles acceleration in relativistic magnetic reconnection sites using an hybrid particle-fluid code, showing that magnetic reconnection is a good candidate for particle acceleration in astrophysical sources. Dependence on plasma σ, guide field and resistivity has been studied, showing that magnetic reconnection is a more general and universal acceleration process than diffusive shock acceleration.