Bipolar magnetic regions on the solar surface are believed to correspond to the topmost portions of Ω-shaped arching flux tubes that have risen buoyantly from the base of the solar convection zone, where strong toroidal magnetic fields are being generated by the dynamo process. The dynamic evolution of such rising flux tubes in the solar convection zone has been studied extensively using a simplified 1D thin flux tube model, and more recently with direct multidimensional MHD simulations. In this paper we review some recent results of MHD simulations of the formation and dynamic rise of buoyant Ω-loops in the solar convection zone. We discuss results with regard to the following topics: (1) the formation of buoyant flux tubes from a horizontal magnetic layer at the base of the solar convection zone due to the growth of the buoyancy instabilities, (2) the necessary twist for maintaining cohesion of the rising flux tubes, (3) the kink evolution of highly twisted emerging tubes, (4) the influence of 3D stratified convection on the rise and the structure of buoyant flux tubes, and finally (5) the emergence of twisted magnetic flux tubes into the solar atmosphere.
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