Evolution of flare ribbons and energyrelease Original Research Article

We examined the relation between the evolutions of the Hα flare ribbons and the released magnetic energiesat a solar flare which occurred on 2001 April 10. This is the first study to evaluate the released energy quantitatively, based on the magnetic reconnection model, and by using the data obtained with the multi wavelength observation. We measured the, photospheric magnetic field strengths and the separation speeds of the fronts of the Hα flare ribbon, and compared them the nonthermal behaviors observed in HXRs and microwaves. Those nonthermal radiation sources tell us when and where large energy releases occur. Then, by using the photospheric and chromospheric features, we estimated the released magnetic energy at the flare. The estimated energy release rates at the Hα kernels associated with the HXR sources are locally large enough to explain the difference between the spatial distribution the Hα kernels and the HXR sources. Their temporal evolution of the energy release rates also shows peaks corresponding to HXR bursts.