Cosmic Ray Injection in a Realistic Galactic Disk

Cosmic rays and magnetic fields provide a significant contribution to the energy density of the Milky Way's interstellar medium (ISM). Through the Parker instability, these non-thermal components compress the thermal ISM into clumps near the disk's midplane and create magnetic lobes perpendicular to the midplane. However, the Parker instability takes a long time, >200 Myr, to develop through linear perturbations to an isothermal slab under vertical hydrostatic equilibrium. The vertical equilibrium is disrupted in a shorter time, ~100 Myr, when triggered by cosmic ray injection from energetic events like supernovae. But even this time is long enough to suggest larger scale phenomena (e.g. galactic rotation) could minimize the observational traces of the effects of cosmic rays and magnetic fields. However, this reasoning neglects the possibility the injection drives change in a shorter time when coupled with other dynamical phenomena in a multi-phase ISM. To understand if this coupling is possible, we use 3D ideal magnetohydrodynamic simulations to study the movement of a buoyant, cosmic ray loaded magnetic flux tube in a realistic galactic disk. These are local simulations of a Cartesian slab, representing a patch of a galactic disk. Comparing different simulation runs, we examine how the buoyant flux tube's movement changes when including the effects of (1) galactic rotation, (2) density waves, (3) clumpy ISM structure, and (4) multiple ISM phases. Simulation methodology and preliminary results will be presented.