PIC methods in astrophysics: PIC simulations of relativistic jets and kinetic physics in astrophysical systems.

The Particle-In-Cell (PIC) method has been developed by Oscar Buneman, Charles Birdsall, Roger W. Hockney, and John Dawson in the 1950s and, with the advances of computing power, has been further developed for several fields such as astrophysical, magnetospheric as well as solar plasmas and recently also for atmospheric and laser physics. Currently more than 15 semi-public PIC codes are available. Its applications have grown extensively with increasing computing power available on high performance computing facilities around the world. These systems allow the study of various topics of astrophysical plasmas, such as magnetic reconnection, pulsars and black hole magnetosphere, non-relativistic and relativistic shocks, relativistic jets, and laser physics. In this review, we describe the PIC method based on Buneman's code and refer to further literature for details such that readers understand how PIC codes work. Especially, we focus on reviewing PIC simulations of relativistic jets and closely related topics until 2020 with emphasizing on the physics involved in the simulations.