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Some preliminary processing results are presented for a dataset obtained withthe Solar Optical Telescope on the Hinode satellite. The idea of the project isto record, nearly simultaneously, the full velocity and magnetic-field vectorsin growing active regions and sunspot groups at a photospheric level. Ourultimate aim is to elaborate observational criteria to distinguish between themanifestations of two mechanisms of sunspot-group formation --- the rising ofan Omega-shaped flux tube of a strong magnetic field and the in situamplification and structuring of magnetic field by convection (the convectivemechanism is briefly described). Observations of a young bipolar subregiondeveloping within AR 11313 were carried out on 9--10 October 2011. Based on theseries of filtergrams, the trajectories of corks are computed, using atechnique similar to but more reliable than local correlation tracking (LCT),and compared with the magnetic maps. At this stage of the investigation, onlythe vertical magnetic field and the horizontal flows are used for a qualitativeanalysis. According to our preliminary findings, the velocity pattern in thegrowing active region has nothing to do with a spreading flow on the scale ofthe entire bipolar region, which could be expected if a tube of strong magneticfield emerged. No violent spreading flows on the scale of the entire growingmagnetic region can be identified. Instead, normal mesogranular andsupergranular flows are preserved. The observed scenario of evolution seems toagree with Bumba's inference that the development of an active region does notentail the destruction of the existing convective-velocity field. Theconvective mechanism appears to be better compatible with observations than therising-tube mechanism.

Doubts about the crucial role of the rising-tube mechanism in the formation of sunspot groups