The line ratio method as a possible tool for more reliable forecasting solar flashes

Abstract

Already published and new observational data are given, which indicate that in the regions of solar flares there is a significant difference in the sub-telescopic structure of the magnetic field, which is absent in non-flare regions. In particular, the magnetic fields by the FeI 6301.5 and FeI 6302.5 Å lines measured in flares outside sunspot umbra have an inverse ratio of Bobs(6301.5) < Bobs(6302.5), while without flares it is mostly Bobs(6301.5) > Bobs(6302.5). The conclusion is argued that in flares this is due to the fact that at the photospheric level there is a spatially unresolved contact of flux tubes with “kilogauss” fields and the weaker background field, which have opposite magnetic polarities. Direct observational indications of particularly strong fields of opposite polarity are found in the far wings of the FeI 6173.3 Å line. New unique observational data relating to the region of the seismic source in the exceptionally powerful solar flare of October 28, 2003 of X17.2/4B class indicate that the above inverse line ratio is most significant precisely in the region of this source. A new idea for more reliable forecasting of solar flares is proposed, which boils down to the fact that new relevant information for forecasting should be obtained from monitoring observational data in the FeI 6301.5 and FeI 6302.5 Å lines.