Evolution H-alpha Flare Kernels and Energy Release
Ayumi Asai, Takaaki Yokoyama, Masumi Shimojo, Satoshi Masuda,
Kazunari Shibata
The investigation of the evolution of H-alpha kernels allows us to
derive some keys of the energy release and the particle acceleration
mechanisms during a flare. We report a detailed examination about the
relationship between the evolution of the H-alpha flare ribbons and
the released magnetic energy during an X2.3 solar flare which occurred
on 2001 April 10. In the H-alpha images, several bright kernels were
observed in the flare ribbons. Based on the magnetic reconnection
model, we could calculate quantitatively the released energy by using
the photospheric magnetic field strengths and separation speeds of the
fronts of the H-alpha flare ribbons. We confirmed that the estimated
energy release rate well corresponds to the bursts in the lightcurves
of nonthermal emission and the spatial distribution of the radiation
sources. We also examined the downward motions which are observed at
the H-alpha kernels. The "red-asymmetry" is generated by the
precipitation of the nonthermal particles and/or thermal conduction
into the chromospheric plasma. We found that the stronger the
red-asymmetry is, the brighter the H-alpha kernel is.
Correspondence
Ayumi Ayumi (asai@nro.nao.ac.jp), Nobeyama Solar Radio Observatory
presentation
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