Magnetohydrodynamic turbulence in accretion disks

Recent work on the structure of magnetic fields in a turbulent medium gives predictions for the properties of the magnetic flux tubes as a function of the Mach number and scale of the turbulence, and the resistivity and viscosity of the fluid. Here I discuss the implications of this work for accretion disks. I show that although accretion disk flux tubes are usually almost completely evacuated, they are nevertheless less buoyant than previous …