  We studied the formation of a pore in AR NOAA 11462. We analysed data
obtained with the IBIS at the DST on April 17, 2012, consisting of full Stokes
measurements of the Fe I 617.3 nm lines. Furthermore, we analysed SDO/HMI
observations in the continuum and vector magnetograms derived from the Fe I
617.3 nm line data taken from April 15 to 19, 2012. We estimated the magnetic
field strength and vector components and the LOS and horizontal motions in the
photospheric region hosting the pore formation. We discuss our results in light
of other observational studies and recent advances of numerical simulations.
The pore formation occurs in less than 1 hour in the leading region of the AR.
The evolution of the flux patch in the leading part of the AR is faster (< 12
hour) than the evolution (20-30 hour) of the more diffuse and smaller scale
flux patches in the trailing region. During the pore formation, the ratio
between magnetic and dark area decreases from 5 to 2. We observe strong
downflows at the forming pore boundary and diverging proper motions of plasma
in the vicinity of the evolving feature that are directed towards the forming
pore. The average values and trends of the various quantities estimated in the
AR are in agreement with results of former observational studies of steady
pores and with their modelled counterparts, as seen in recent numerical
simulations of a rising-tube process. The agreement with the outcomes of the
numerical studies holds for both the signatures of the flux emergence process
(e.g. appearance of small-scale mixed polarity patterns and elongated granules)
and the evolution of the region. The processes driving the formation of the
pore are identified with the emergence of a magnetic flux concentration and the
subsequent reorganization of the emerged flux, by the combined effect of
velocity and magnetic field, in and around the evolving structure.
