2008ApJ...684L..57L

We have performed nonlinear ideal magnetohydrodynamic simulations of the long-term evolution of a magnetized low-density ``bubble'' plasma formed by a radio galaxy in a stratified cluster medium. It is found that about 3.5% of the initial magnetic energy remains in the bubble after ∼8x10<sup>9</sup> yr, and the initial magnetic bubble expansion is adiabatic. The bubble can survive for at least 8x10<sup>9</sup> yr due to the stabilizing effect of the bubble magnetic field on Rayleigh-Taylor and Kelvin-Helmholtz instabilities, possibly accounting for ``ghost cavities'' as observed in Perseus A. A filament structure spanning about 500 kpc is formed along the path of bubble motion. The mean value of the magnetic field inside this structure is ∼0.88 µG at ∼8x10⁹ yr. Finally, the initial bubble momentum and rotation have limited influence on the long-term evolution of the bubble.