Intensification of long-period geomagnetic fluctuations associated with Solar flares

Abstract:

In periods of quiet-time geomagnetospheric situation (|Dst| < 20nT ) for intervals prior to extreme Solar flares spectral analysis of minute data of the horizontal component of the geomagnetic field recorded in the wide geographic range (latitude geom. 31⁰-64⁰) was made. Used material includes data for 20 extreme Solar flares from catalog http://vso.nso.edu/cgi/catalogui, registered in 2001-2005. Facts of synchronization wavelet skeletons spectral images of  long-period geomagnetic pulsations observed for several days prior to the development extreme Solar flares. For objective assessment of the degree of synchronization of the wavelet skeleton spectra of vibrational modes at geomagnetic stations an original spectral correlation algorithm was proposed. Number of synchronizations wavelet skeleton images on all the magnetic stations is presented in the form of histograms of time preceding the occurrence of intense flares. Histograms for pulsations in the period range of 2-120 and 2-180 minutes have maxima for 2 and 3.5 days of occurrence of Solar flares. They as geomagnetic precursors of flarecan be regarded. Mechanism of such fluctuations and their subsequent synchronization can serve vibrational enhancement of ionospheric current systems due to the increase of the ionospheric conductivity due to Solar ionizing electromagnetic radiation of extreme Solar flare. The results obtained to develop a method for prediction of Solar flare activity can be used.