Evolution of the magnetic field B_LOS from PHI observations in the region of interest near the large negative sunspot from 09:05 to 09:55 UT. Several magnetic polarities (labeled C1–C4) originate close to the sunspot. These polarities and the big negative N1-N2 show a motion towards each other over time. Four double-headed arrows are drawn in panel (f) such that the arrowheads touch two opposite-polarity patches. The same arrows are drawn on panels (a), (b), (c), and (e) for each of the C1–C4 patches. By comparing these panels with panel (f), it can be seen that the opposite polarities move closer to each other and magnetic flux convergence is increasing.