The interplanetary origins of geomagnetic storm with [formula omitted] during solar cycle 24 (2009–2019)

Abstract

In this study, we analyzed 149 geomagnetic storms of moderate and intensity (i.e., Dstmin≤-50nT) occurred during the solar cycle 24 from 2009 to 2019, and identified their interplanetary sources. Among them, there are 20 strong storms with -200nT≤Dstmin≤-100nT, and 2 super–strong storms with Dstmin≤-200nT. We have found that corotating interaction regions (CIRs) account for 37% (55/149) of geomagnetic storms, interplanetary coronal mass ejections (ICMEs) result in 30% (45/149) of geomagnetic storms and sheath regions (SH) are responsible for 15% (23/149) of geomagnetic storms. Meanwhile, 18/20 of the strong storms are caused by the structures associated with interplanetary coronal mass ejections (ICME, SH, and SH + ICME), while the CIR constitutes only to 2/20 of the strong storms. It is found that the two super–strong geomagnetic storms are caused by the SH + ICME. Our findings also suggest that geomagnetic storms in different periods of solar activity are caused by different interplanetary structures, which is consistent with previous research. In comparison to solar cycle 23, there is no substantial geomagnetic storm induced by CIR during the dwindling and subsiding phases of solar cycle 24. In the descending stage, the proportion of moderate events caused by ICME decreases, and ICMEs cause no super–strong event. In ascending stage, neither strong nor super strong events occur.