Rising Jet-Inflated Bubbles in Clusters of Galaxies
  We conduct two-dimensional axisymmetric (referred to as 2.5D) hydrodynamical numerical simulations of bubble evolution in clusters of galaxies. We inflate bubbles using slow, massive jets with a wide opening angle, and follow their evolution as they rise through the intra-cluster medium (ICM). We find that these jet-inflated bubbles are quite stable, and can reach large distances in the cluster while still maintaining their basic structure. The stability of the jet-inflated bubble comes mainly from the dense shell that forms around it during it's inflation stage, and from the outward momentum of the bubble and the shell. On the contrary, bubbles that are inserted by hand onto the grid and not inflated by a jet, i.e., an artificial bubble, lack these stabilizing factors, therefore, they are rapidly destroyed. The stability of the jet-inflated bubble removes the demand for stabilizing magnetic fields in the bubble. 
Assaf Sternberg (Technion, Israel) Noam Soker (Technion, Israel)