Prof. Kenichi Nishikawa (Alabama A&M University)

3D PIC simulations for relativistic jets with a toroidal magnetic field and associated synthetic spectra and polarizations

Particle-in-Cell simulations can provide a possible answer to an important key issue of astrophysical plasma jets, i.e., how a toroidal magnetic field affects the evolution of pair and electron-ion jets associated to the acceleration of particles. We show that Weibel, mushroom, and kinetic Kelvin-Helmholtz instabilities excited at the linear stage, generate a quasi-steady electric field component along the jet, which accelerates and decelerates electrons. We find that the two different jet compositions (pair and electron-ion) generate different instability modes respectively and observe significant differences in the structure of the strong electromagnetic fields that are driven by the kinetic instabilities with the pair jet. 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 manifestation.