4:15 PM - 4:30 PM
[PEM30-05] Particle acceleration and magnetic field generation in the relativistic jet-plasma interactions
Keywords:Relativistic jets, Particle acceleration, Magnetic field generation, Weibel instability
The aim of the current work is to analyze particle acceleration and magnetic field generation related to propagation of a relativistic electron-ion jet front into an unmagnetized ambient electron-ion plasma. We have focused on the earliest evolution in shock formation. The analysis is on the basis of a three-dimensional relativistic electromagnetic particle-in-cell (PIC) code. The results demonstrate that the Weibel instability is responsible for generation of strong small-scale magnetic fields and subsequent particles acceleration. In agreement with previous studies the majority of the particles acceleration occurs behind the jet front. Initially, the incoming electrons respond to field fluctuations growing as a result of the Weibel instability. Therefore, the electron channels are generated and the total magnetic energy grows linearly due to the mutual attraction between the channels, and downstream advection of the magnetic field fluctuations. When the magnetic fields become strong enough to deflect the much heavier ions, the linear growth rate of instability decreases as a result of oppositely directed electron-ion currents and topological change in the structure of magnetic fields. The Ion channels are then merged and magnetic energy increases more slowly at the expense of the energy stored in ion stream. It has been clearly illustrated that the ion channels develop through a larger scale in the longitudinal direction, while extension of the electron filaments is limited. Hence, the ions channels are the sources of deeply penetrating magnetic fields. Our results are in valid agreement with those reported in the literature.