The Solar Event of 14 – 15 July 2012 and Its Geoeffectiveness

Abstract

During Solar Cycle 24, which started at the end of 2008, the Sun was calm, and there were not many spectacular geoeffective events. In this article, we analyze the geomagnetic storm that happened on 15 July 2012 during the 602nd anniversary of the Polish Battle of Grunwald, thus we propose this event to be called the “Battle of Grunwald Day Storm”. According to NOAA scale, it was a G3 geomagnetic storm with a southward component of the heliospheric magnetic field, $Bz$ B z , falling to −20 nT, minimum Dst index of −139 nT, AE index of 1368 nT, and Ap index of 132 nT. It was preceded by a solar flare class X1.4 on 12 July. This geomagnetic storm was associated with the fast halo coronal mass ejection at 16:48:05 UT on 12 July, first appearance in the Large Angle and Spectroscopic Coronagraph C2, with a plane-of-sky speed of 885 km s−1 and maximum of 1415 km s−1. This geomagnetic storm was classified as the fourth strongest geomagnetic storm of Solar Cycle 24. At that time, a significant growth in the failures of the Polish electric transmission lines was observed, which could have a solar origin.

Association of the Main Phase of the Geomagnetic Storms in Solar Cycles 23 and 24 With Corresponding Solar Wind‐IMF Parameters

“…As introduced in Section 1, several scientists (e.g., Gil et al., 2020; Gopalswamy et al., 2015; Hajra, 2021; Liu et al., 2015; Scolini et al., 2018; Watari, 2017) studied the occurrence and intensity of the geomagnetic activity in the weakest solar cycle 24 in 100 years. Liu et al.…”

Signs of geoeffective space weather events in cosmic rays during the first half of the solar cycle 24

“…We analyze the geomagnetic storm which happened on July 15 of 2012 in the 602 anniversary of the famous Polish Battle of Grunwald. Thus we propose the name for this event 'Battle of Grunwald day' (Gil et al 2020b). According to the NOAA scale, it was a G3 geomagnetic storm with the Bz heliospheric magnetic field component dropping to -20 nT, Dst index -139 nT, AE index to 1368 nT and Ap index 132 nT.…”

Double Superposed Epoch Analysis of Geomagnetic Storms and Corresponding Solar Wind and IMF in Solar Cycles 23 and 24

“…The solar cycle 24 (SC24, 2010–2019) was the weakest solar cycle in 100 years with the peak solar activity being ∼32% less intense compared to the previous solar cycle 23 (SC23), Figure 1. Several scientists studied the geomagnetic storms in SC24 (e.g., Gil et al., 2020; Gopalswamy et al., 2015; Hajra, 2021; Liu et al., 2015). From these studies it is known that the storms were less frequent and less intense in SC24.…”

“…Gil et al. (2020) studied the comparatively weak storm of 15 July 2012 of intensity only −139 nT. Hajra (2021) compared the number of storms in SC24 with those in the previous solar cycles 20–23.…”

“…The superposed epoch analysis has been used by several scientists for studying the geomagnetic storms (e.g., Hutchinson et al, 2011;Yermolaev et al, 2010;Yokoyama and Kamide, 1997). Keesee et al (2014) used the epoch analysis to study the variation of the global ion temperature during the ICME driven and CIR driven storms in 2008-2012. Hutchinson et al (2011 conducted the epoch analysis on the intensity of the storms and corresponding solar wind mechanisms in SC23 (1997SC23 ( -2008.…”