  We present results from 3D visco-resistive magnetohydrodynamic (MHD)
simulations of the emergence of a convection zone magnetic flux tube into a
solar atmosphere containing a pre-existing dipole coronal field, which is
orientated to minimize reconnection with the emerging field. We observe that
the emergence process is capable of producing a coronal flux rope by the
transfer of twist from the convection zone as found in previous simulations. We
find that this flux rope is stable, with no evidence of a fast rise, and that
its ultimate height in the corona is determined by the strength of the
pre-existing dipole field. We also find that although the electric currents in
the initial convection zone flux tube are almost perfectly neutralized, the
resultant coronal flux rope carries a significant net current. These results
suggest that flux tube emergence is capable of creating non-current-neutralized
stable flux ropes in the corona, tethered by overlying potential fields, a
magnetic configuration that is believed to be the source of coronal mass
ejections.
