Title:

Evolution of flare ribbons and energy release

Authors:　Asai, A.; Masuda, S.; Yokoyama, T.; Shimojo, M.; Kurokawa, H.; Ishii, T. T.; Shibatal, K.

Abstract

We examined the relation between the evolutions of the Halpha flare ribbons and the released magnetic energies at 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 Halpha 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 Halpha kernels associated with the HXR sources are locally large enough to explain the difference between the spatial distribution the Halpha kernels and the HXR sources. Their temporal evolution of the energy release rates also shows peaks corresponding to HXR bursts.