TITLE:
Characteristic Study of Intense Storms: Case of the Intense Storms of November 6, 1997, August 17, 2001, and January 7, 2015
AUTHORS:
Karim Guibula, Abidina Diabate, Rassiratou Kindo, Frédéric Ouattara
KEYWORDS:
Geomagnetic Storms, Intense Storms, Bz Component, Geomagnetic Indices, Solar Wind
JOURNAL NAME:
Open Journal of Applied Sciences,
Vol.15 No.9,
September
3,
2025
ABSTRACT: The characteristics of three intense geomagnetic storms and the influence of solar phases on their intensity were studied. The extreme values of the Dst and AE indices and solar wind parameters (Vsw, Psw, Bz, Ey, nP) were used to characterize the storm intensities. The three storms were selected during the solar ascending, maximum, and descending phases, respectively, and with almost identical minimum Dst values. The results show that storm of August 17, 2001, occurring at solar maximum with a prolonged (~10 h) and well-structured south-facing Bz (Bzsouth), is the most intense. Storm of November 6, 1997, occurring during the ascending phase and characterized by a prolonged (~12 h) but less structured Bzsouth, and storm of January 7, 2015, occurring during the descending phase and characterized by a well-structured but less prolonged (~5 h) Bzsouth, are the least intense. It is also observed that intense storms occurring at different solar phases do not have the same characteristics or intensity. These results confirm the importance of solar phases as well as that of the Bz component of the interplanetary magnetic field (IMF), in particular its structure in CMEs and the duration of its southern polarity, in determining the intensity of geomagnetic storms.