The white-light flares 1999 June 26 and 1991 June 15
We represent some observational properties of two white-light flares (WLF) 1991 June 15 and 1999 June 26 and make comparison between them. This is particularly interesting because the first was one of the most powerful flare GOES class X12 and the second was a compact flare GOES class M2.3. The substantial differences of some flare parameters (GOES class, Нα classification, members of WLF kernels and their locations within the sunspot group, size and duration of WLF emission, peak flux density of the microwave radiation) were found. But both these events do have about the same magnitude of the emission rate in continuum at λ658.0 nm: Е = 1.5 ⋅ 107 and 1.1 ⋅ 107erg cm-2 c-1 nm-1 . There is generally a good temporal coincidence between HXR and WLF emission during the impulsive phase, but light curve of the WLF emission of 1999 June 26 flare shows a stronger temporal correlation with 14–23 keV emission. According to their spectral features both flares can be classified as a type I white-light flares.
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