  Some preliminary processing results are presented for a dataset obtained with
the Solar Optical Telescope on the Hinode satellite. The idea of the project is
to record, nearly simultaneously, the full velocity and magnetic-field vectors
in growing active regions and sunspot groups at a photospheric level. Our
ultimate aim is to elaborate observational criteria to distinguish between the
manifestations of two mechanisms of sunspot-group formation --- the rising of
an Omega-shaped flux tube of a strong magnetic field and the in situ
amplification and structuring of magnetic field by convection (the convective
mechanism is briefly described). Observations of a young bipolar subregion
developing within AR 11313 were carried out on 9--10 October 2011. Based on the
series of filtergrams, the trajectories of corks are computed, using a
technique similar to but more reliable than local correlation tracking (LCT),
and compared with the magnetic maps. At this stage of the investigation, only
the vertical magnetic field and the horizontal flows are used for a qualitative
analysis. According to our preliminary findings, the velocity pattern in the
growing active region has nothing to do with a spreading flow on the scale of
the entire bipolar region, which could be expected if a tube of strong magnetic
field emerged. No violent spreading flows on the scale of the entire growing
magnetic region can be identified. Instead, normal mesogranular and
supergranular flows are preserved. The observed scenario of evolution seems to
agree with Bumba's inference that the development of an active region does not
entail the destruction of the existing convective-velocity field. The
convective mechanism appears to be better compatible with observations than the
rising-tube mechanism.
