The Parker Instability with Cosmic Ray Streaming

The Parker Instability is a Rayleigh-Taylor like mode where the magnetic field and cosmic rays support the thermal gas against gravity. The effect of cosmic ray transport on stratified systems had not been analyzed. Therefore we performed a stability analysis on the Parker Instability for three different cosmic ray transport models: decoupled from the gas, coupled with $\gamma_c=4/3$ but not streaming, and finally coupled with streaming at the Alfv\'{e}n speed. When the compressibility of the cosmic rays is decreased the system becomes much more stable, but the addition of cosmic ray streaming to the Parker Instability severely destabilizes it. Through comparison of these three cases and analysis of the work contributions for the perturbed quantities of each system, we demonstrated that cosmic ray heating of the gas is responsible for the destabilization of the system. Currently, we are working to run numerical simulations of the instability. Through these simulations, we aim to add in more effects like radiative cooling and diffusion as well as observe any nonlinearity that appears in the instability.