ИСТИНА

We review the geomagnetic pulsations produced by hard electromagnetic radiation of solar flares. It is well known that powerful solar flares are accompanied by sharply amplified electromagnetic radiation in the frequency range from long radio waves to X-ray and gamma radiation that leads to a sharp increase in the electron content in the entire column of the ionosphere and to geophysical phenomena known generally as sudden ionospheric disturbances (SIDs). A component of SIDs is the geomagnetic solar flare effect (SFE). SFE is caused by a sharply increased intensity of ionospheric currents at different heights (mainly D and E layers) and, especially, by amplified Sq-currents. We studied spatial features of SFE electric current systems and related geomagnetic pulsations (Psfe) on the base of experimental data from the 30 most powerful solar flares (> X5 class). We performed a detailed analysis of the geomagnetic response to the hard electromagnetic radiation from X29 solar flare on November 4, 2003 and from the X17 flare on September 7, 2005 [1]. It was shown that during the flares emitting intense X- and gamma-rays, the SFE and Psfe pulsations were observed globally, including the night hemisphere and high latitudes at the Earth’s surface as well as in the inner magnetosphere. Long-period P3sfe pulsations with periods from ~ 200 to 600 s are rather related to γ-radiation from solar flares. They are recorded from equatorial latitudes to dayside polar cap. Possible physical mechanisms of the gamma solar flare effect are discussed. References [1] V.A. Parkhomov, A.V. Dmitriev, P.M. Klimov, Spatial Features of SFE Current Systems and Geomagnetic Pulsations Psfe Related to Gamma Radiation From Solar Flares, Chapter 4 in Gamma Rays: Technology, Applications and Health Implications, Ed. I. Bikit, NOVA Science Publishers, Inc., New York, ISBN: 978-1-62257-706-4, 2013.