We use three-dimensional simulations to study compressible convection
in a rotating frame with magnetic fields and overshoot into surroundin
g stable layers. The, initially weak, magnetic field is amplified and
maintained by dynamo action and becomes organized into flux tubes that
are wrapped around vortex tubes. We also observe vortex buoyancy whic
h causes upward flows in the cores of extended downdraughts. An analys
is of the angles between various vector fields shows that there is a t
endency for the magnetic field to be parallel or antiparallel to the v
orticity vector, especially when the magnetic field is strong. The mag
netic energy spectrum has a short inertial range with a slope compatib
le with k(+1/3) during the early growth phase of the dynamo. During th
e saturated state the slope is compatible with k(-1). A simple analysi
s based on various characteristic timescales and energy transfer rates
highlights important qualitative ideas regarding the energy budget of
hydromagnetic dynamos.