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We carried out a multi-wavelength study of a CME and a medium-size 1B/C1.3flare occurring on 12 May 1997. We present the investigation of magnetic-fieldvariations in the NOAA Active Region 8038 which was observed on the Sun during7--16 May 1997. Analyses of H{\alpha} filtergrams and MDI/SOHO magnetogramsrevealed continual but discrete surge activity, and emergence and cancellationof flux in this active region. The movie of these magnetograms revealed twoimportant results that the major opposite polarities of pre-existing region aswell as in the emerging flux region (EFR) were approaching towards each otherand moving magnetic features (MMF) were ejecting out from the major northpolarity at a quasi-periodicity of about ten hrs during 10--13 May 1997. Theseactivities were probably caused by the magnetic reconnection in the loweratmosphere driven by photospheric convergence motions, which were evident inmagnetograms. The magnetic field variations such as flux, gradient, and sunspotrotation revealed that free energy was slowly being stored in the corona. Theslow low-layer magnetic reconnection may be responsible for this storage andthe formation of a sigmoidal core field or a flux rope leading to the eventualeruption. The occurrence of EUV brightenings in the sigmoidal core field priorto the rise of a flux rope suggests that the eruption was triggered by theinner 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 innercorona, which is consistent with the temporal profile of the reconnectionelectric field. In conclusion, we propose a qualitative model in view offramework of a solar eruption involving, mass ejections, filament eruption,CME, and subsequent flare.

Probing the Role of Magnetic-Field Variations in NOAA AR 8038 in Producing Solar Flare and CME on 12 May 1997