  We carried out a multi-wavelength study of a CME and a medium-size 1B/C1.3
flare occurring on 12 May 1997. We present the investigation of magnetic-field
variations in the NOAA Active Region 8038 which was observed on the Sun during
7--16 May 1997. Analyses of H{\alpha} filtergrams and MDI/SOHO magnetograms
revealed continual but discrete surge activity, and emergence and cancellation
of flux in this active region. The movie of these magnetograms revealed two
important results that the major opposite polarities of pre-existing region as
well as in the emerging flux region (EFR) were approaching towards each other
and moving magnetic features (MMF) were ejecting out from the major north
polarity at a quasi-periodicity of about ten hrs during 10--13 May 1997. These
activities were probably caused by the magnetic reconnection in the lower
atmosphere driven by photospheric convergence motions, which were evident in
magnetograms. The magnetic field variations such as flux, gradient, and sunspot
rotation revealed that free energy was slowly being stored in the corona. The
slow low-layer magnetic reconnection may be responsible for this storage and
the formation of a sigmoidal core field or a flux rope leading to the eventual
eruption. The occurrence of EUV brightenings in the sigmoidal core field prior
to the rise of a flux rope suggests that the eruption was triggered by the
inner tether-cutting reconnection, but not the external breakout reconnection.
An impulsive acceleration revealed from fast separation of the H{\alpha}
ribbons of the first 150 seconds suggests the CME accelerated in the inner
corona, which is consistent with the temporal profile of the reconnection
electric field. In conclusion, we propose a qualitative model in view of
framework of a solar eruption involving, mass ejections, filament eruption,
CME, and subsequent flare.
