  Current coronal mass ejection (CME) models set their lower boundary to be in
the lower corona. They do not calculate accurately the transfer of free
magnetic energy from the convection zone to the magnetically dominated corona
because they model the effects of flux emergence using kinematic boundary
conditions or simply assume the appearance of flux at these heights. We test
the importance of including dynamical flux emergence in CME modeling by
simulating, in 2.5D, the emergence of sub-surface flux tubes into different
coronal magnetic field configurations. We investigate how much free magnetic
energy, in the form of shear magnetic field, is transported from the convection
zone to the corona, and whether dynamical flux emergence can drive CMEs. We
find that multiple coronal flux ropes can be formed during flux emergence, and
although they carry some shear field into the corona, the majority of shear
field is confined to the lower atmosphere. Less than 10% of the magnetic energy
in the corona is in the shear field, and this, combined with the fact that the
coronal flux ropes bring up significant dense material, means that they do not
erupt. Our results have significant implications for all CME models which rely
on the transfer of free magnetic energy from the lower atmosphere into the
corona but which do not explicitly model this transfer. Such studies of flux
emergence and CMEs are timely, as we have new capabilities to observe this with
Hinode and SDO, and therefore to test the models against observations.
