Abstract
We present the results of studying the proton flare 2B/X4.8 on 23 July 2002, observed with the Large Solar Vacuum Telescope (LSVT) at the Baikal Astrophysical Observatory in spectropolarimetric mode with high spatial and spectral resolution. We have found some evidence for Hα line impact linear polarization, predominantly during the initial moments of the flare. For the Hα line 606 cuts were made along the dispersion in 53 spectrograms, and a polarization signal was found more or less confidently in 60 cuts (13 spectrograms). Polarization was mainly observed in one of the kernels of the flare. A particular feature of this kernel was that the Hα line was observed to show a reversal in the central part of this kernel, which created a dip in the kernel center in the photometric cut. The size of these dips and the size of the sites with the linear polarization coincide and are equal to 3 – 6 arcsec. The maximum polarization degree in this kernel reached 15 %. The direction of the polarization in the kernel is radial, except for the first two frames, where the direction of the polarization was both radial and tangential. Furthermore, we found an analogy between the effects observed at the chromospheric level in this kernel (polarization and depression in Hα line) and the temporal variation of the HXR sources.
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Firstova, N.M., Polyakov, V.I. & Firstova, A.V. Hα Line Impact Linear Polarization Observed in the 23 July 2002 Flare with the Large Solar Vacuum Telescope (LSVT). Sol Phys 279, 453–464 (2012). https://doi.org/10.1007/s11207-012-0037-2
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DOI: https://doi.org/10.1007/s11207-012-0037-2