Study of the evolution of the geomagnetic disturbances during the passage of high-speed streams from coronal holes in solar cycle 2009-2016

Abstract

We study the geo-effectiveness of high-speed streams (HSS) detected during the consecutive eight years (2009 - 2016) period of solar cycle 24. These HSS are of different speeds and durations. During their passage, solar wind plasma and magnetic field parameters are also not similar. We utilize solar wind plasma and magnetic field parameters during the HSS passage in addition to two geomagnetic indices. Using the superposed-epoch analysis method, we study the time-evolution of geomagnetic disturbances concerning various solar wind parameters during the passage of HSS of different speeds and durations. We identify the solar wind parameter, which best follows the variations in geomagnetic parameters during the evolution of geomagnetic storms, from the start till recovery. Further, utilizing the level of geomagnetic activity due to individual HSS, we also search for solar wind parameter/function, which best correlates with the strength of geomagnetic storms due to these HSS.