Magnetic Reconnection in Relativistic Astrophysical Jets

Abstract:

We investigate the physics of magnetic reconnection in relativistic astrophysical jets, by means of first-principles particle-in-cell (PIC) kinetic simulations. In magnetically-dominated jets, magnetic reconnection is often invoked as a mechanism to dissipate the jet magnetic energy into plasma thermal energy, thus powering the observed emission. With 2D and 3D PIC simulations, we show that magnetic reconnection in relativistic astrophysical jets can efficiently accelerate the particles up to extreme energies, generating a flat power-law tail with slope between -2 and -1. We discuss the dependence of the particle acceleration efficiency on the flow magnetization (in the regime sigma>>1 of magnetically-dominated jets), the composition (electron-positron or electron-proton plasma) and the strength of the "guide field" orthogonal to the alternating fields. Our results place important constraint on the physics of magnetic reconnection in relativistic astrophysical jets.