Global disturbance of Earth’s magnetosphere and its connection with space weather

Abstract

This paper deals with extreme conditions of the global magnetosphere disturbance: very quiet and greatly disturbed, and their relationship with interplanetary medium parameters. The degree of global magnetosphere disturbance was estimated from the monthly and annual number of magnetically quiet and magnetically disturbed days. The cyclic and seasonal distributions of magnetically quiet and disturbed days were compared, and their relationship with interplanetary medium parameters in solar cycles 20–24 was analyzed. Magnetically quiet days are shown to be mainly observed at the ascending phase of solar activity and during the winter solstice season. Magnetically disturbed days dominate at the descending phase of the solar cycle and during the equinox season. An anomalously large increase in the number of quiet days was found in solar cycle 24 as compared to previous cycles. It has been established that the cyclic variation in the annual number of quiet and disturbed days is determined by the behavior and magnitude of the speed, temperature, dynamic pressure of solar wind plasma and the interplanetary magnetic field modulus. The detected burst in the number of quiet days during the ascending phase of solar cycle 24 is assumed to reflect internal processes on the Sun and related changes in interplanetary medium parameters. The patterns of cyclical and seasonal variation in the number of magnetically quiet and disturbed days and their relationship with the solar wind parameters can be used to predict space weather.

The PC Index Variations During 23/24 Solar Cycles: Relation to Solar Wind Parameters and Magnetospheric Disturbances

“…It is remarkable that analogous result was obtained by Kurazhkovskaya (2020) when examining correlation between the yearly number of magnetically disturbed days ( Nd ) and the solar wind parameters during 20–24 solar cycles. Below we point to coefficients of correlation between Nd and particular solar wind parameters estimated by Kurazhkovskaya (2020) in comparison with correlation between the same parameter and PC index (in brackets): for solar wind speed Vsw , R = 0.78 (0.86); for solar wind density Nsw , R = 0.30 (−0.27); for solar wind dynamic pressure Pdyn , R = 0.8 (0.83); for southward IMF Bz component, R = 0.25 (0.72); for total IMF field |B| , R = 0.76 (0.84); and for sunspot number, R = 0.37 (0.57). Referring to precedent of the E KL field, we come to conclusion that the higher efficiency of total IMF field | B | in comparison the IMF Bz component is determined by the strong influence of IMF By component on the solar wind‐magnetosphere coupling and, correspondingly, on the solar wind energy income into the magnetosphere.…”