3D PIC Simulations for relativistic jets with a toroidal magnetic field

We have investigated how kinetic instabilities such as the Weibel instability (WI), the mushroom instability (MI), and the kinetic Kelvin-Helmholtz instability (kKHI) are excited in jets without and with a toroidal magnetic field, and how such instabilities contribute to particle acceleration. In this work, we use a new jet injection scheme, where an electric current is self-consistently generated at the jet orifice by the jet particles, which produce the toroidal magnetic field. We perform five different simulations for a sufficiently long time to examine the non-linear effects of the jet evolution. We inject unmagnetized e^± and e^-- p⁺ (m_p/m_e = 1836), as well as magnetized e^± and e^-- i⁺ (m_i/m_e = 4) jets with a top-hat jet density profile into an unmagnetized ambient plasmas of the same species. We show that WI, MI, and kKHI excited at the linear stage, generate a non-oscillatory x-component of the electric field accelerating, and decelerating electrons. We find that the two different jet compositions (e^± and e^-- i⁺) display different instability modes, respectively. Moreover, the magnetic field in the non-linear stage generated by different instabilities is dissipated and reorganized into new topologies. A 3D magnetic field topology depiction indicates possible reconnection sites in the non-linear stage, where the particles are significantly accelerated by the dissipation of the magnetic field associated to a possible reconnection event.