Investigation of the atmospheric structure for the 2011 August 9 white-light flare
We derived some semi-empirical atmospheric models for three white-light flare (WLF) kernels at the time of pre-impulsive and impulsive phases of the 2011 August 9 flare. The model calculations are based on the observations of the continuum emission at 6579 Å and profiles of Hα and FeI photospheric lines. In order to explain the observational brightness of the continuum and line profiles the semi-empirical models of the impulsive WLF kernels require the temperature increase in the lower chromospheric and upper photospheric layers. For the pre-impulsive kernel of WLF the model results show that the most effective heating should be located in the deeper photospheric layers than for the impulsive kernels, but the chromosphere is not strongly heated. Spectral features and model results indicate that the emission of these WLF kernels are difficult to explain by the canonical heating mechanisms that transport the energy from the corona down to deeper atmospheric layers.
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