No abstract

We report the results of monitoring of cosmic rays and geomagnetic field along 210 magnetic meridians in Yakutia in the first half of September 2017. The energy spectrum of solar cosmic rays during Ground Level Enhancement in September 10, 2017 is estimated as J=3027E–1.99exp(–E/729 MeV). We present the results of the forecast and complex analysis of the magnetic storm on September 7–9, 2017 with Dst=–124 nT. The forecast lead time is about one day. We examine how the storm affected the electric potential and VLF signal propagation from RSDN-20 radio navigation stations. Irregular Pi3–Pi1 pulsations occurred during the September 8, 2017 magnetic storm from 12 to 20 UT. The pulsations were accompanied by variations in electrotelluric potentials and geomagnetic fields with the correlation coefficient between them ρ(E, H)=0.5÷0.9. The effects of the magnetic storm manifested themselves as an increase in the attenuation and a decrease in the phase delay of VLF radio signals.

We report the results of monitoring of cosmic rays and geomagnetic field along 210 magnetic meridians in Yakutia in the first half of September 2017. The energy spectrum of solar cosmic rays during Ground Level Enhancement in September 10, 2017 is estimated as J=3027E–1.99exp(–E/729 MeV). We present the results of the forecast and complex analysis of the magnetic storm on September 7–9, 2017 with Dst=–124 nT. The forecast lead time is about one day. We examine how the storm affected the electric potential and VLF signal propagation from RSDN-20 radio navigation stations. Irregular Pi3–Pi1 pulsations occurred during the September 8, 2017 magnetic storm from 12 to 20 UT. The pulsations were accompanied by variations in electrotelluric potentials and geomagnetic fields with the correlation coefficient between them ρ(E, H)=0.5÷0.9. The effects of the magnetic storm manifested themselves as an increase in the attenuation and a decrease in the phase delay of VLF radio signals.

Abstract. Quasi-periodic changes of the geomagnetic field and plasma parameters in the range of Pc 5 pulsations, which occurred immediately after the interaction of interplanetary shock (IPS) with Earth's magnetosphere in the event of April 24, 2009 at 00:53 UT are examined using ground and satellite observations. The pulsations were localized at latitudes 66-74° in the noon (11 MLT) and evening (20 MLT) sectors. The analysis of hodographs of the geomagnetic field changes both from satellite and ground observations has shown the presence of vortical disturbances. In this event, both the IPS front in the interplanetary medium and the compression wave front in the magnetosphere had a slope in the Z GSM =0 plane; the inclination angle was 14° in the interplanetary medium and 34° in the magnetosphere.The location of the vortical disturbances in the magnetosphere at different radial distances, i.e. X~5.5 Re in the noon sector and X ~-6.3 ÷-7.3 Re in the evening sector, is in agreement with the front inclination. As inferred from satellite observations, the maximum intensity of wave disturbances in both the sectors was registered in the toroidal component of the magnetic field. This suggests the resonant mechanism of excitation of these disturbances. The analysis of distribution of velocities of plasma flow and compression wave front propagation in the magnetosphere's equatorial plane has revealed that the vortical disturbances occurred in regions where these velocities were noticeably different in magnitude.

We present results of the analysis of an unusually long narrow-band emission in the