Radiation from particles energized by pinch/kink instabilities in astrophysical jets

We use particle-in-cell simulation to investigate whether nonlinear development of magnetohydrodynamic pinch and kink instabilities could explain observed high-energy radiation from astrophysical jets. We start with a simplified jet model, namely a Z-pinch configuration in relativistically-hot collisionless electron-positron pair plasma, that is unstable to pinch/kink modes. We evolve the system from instability onset through nonlinear development, focusing on the release of magnetic energy to plasma heating and nonthermal particle acceleration (NTPA), and the resulting synchrotron and inverse Compton emission from high-energy particles. Our previous work showed this release occurs in two stages: fast and then slow, with the fast stage dominating particle energization. The instability growth rate and NTPA efficiency are greater for the gas-pressure-balanced Z-pinch than for a force-free screw-pinch configuration, leading us to concentrate on the Z-pinch case during the fast stage. We examine the effect of radiative cooling, as well as radiative signatures for different radiation regimes.