  In the present work we study Hinode/EIS observations of an active region
taken before, during and after a small C2.0 flare in order to monitor the
evolution of the magnetic field evolution and its relation to the flare event.
We find that while the flare left the active region itself unaltered, the event
included a large Magnetic Field Enhancement (MFE), which consisted of a large
increase of the magnetic field to strengths just short of 500~G in a rather
small region where no magnetic field was measured before the flare. This MFE is
observed during the impulsive phase of the flare at the footpoints of flare
loops, its magnetic energy is sufficient to power the radiative losses of the
entire flare, and has completely dissipated after the flare. We argue that the
MFE might occur at the location of the reconnection event triggering the flare,
and note that it formed within 22 minutes of the flare start (as given by the
EIS raster return time). These results open the door to a new line of studies
aimed at determining whether MFEs 1) can be flare precursor events, 2) can be
used for Space Weather forecasts; and 3) what advance warning time they could
allow; as well as to explore which physical processes lead to their formation
and dissipation, whether such processes are the same in both long-duration and
impulsive flares, and whether they can be predicted by theoretical models.
