Advances in Astronomy and Space Physics, Volume 12, Issue 1-2, PP. 25-30 (2022)
doi: 10.17721/2227-1481.12.25-30



Disturbances during a geomagnetic storm: A case study on 7 October 2015

Hasan Şafak Erdağ, Zehra Can

Yildiz Technical University, Faculty of Art & Sciences, Department of Physics, TR-34220 Istanbul, Turkey

Abstract
In this study, we present the detailed study of the geomagnetic storm that occurred 6-10 October 2015. In literature this storm was classified as a two-step storm due to the observation of two large decreases of the disturbance storm time (Dst) index during the main storm phase. In addition, the strong thermal emission velocity enhancement (STEVE) event occurred during the same storm phase was photographically documented by citizen scientists at Minnesota Nevis (USA). The storm of 7 October 2015, which exhibits high-intensity, long-duration, continuous AE activity (HILDCAA), is one of the strongest storms of the recent 24th solar cycle. We examined changes in Dst index, interplanetary magnetic field (IMF) Bz, flow velocity, proton density, solar wind pressure, epsilon parameters and presented the discussion of the physical mechanism happened during this geomagnetic storm. The results obtained for the storm on 7 October 2015 were also compared with geomagnetic storms occurred on 8 March 2008, 25 July 2016 and 8 September 2017.

Keywords:
auroral phenomena, solar wind - magnetosphere interactions, storms and substorms