Solar-Terrestrial Physics Solar-Terrestrial Physics Solar-Terrestrial Physics 2500-0535 23004 10.12737/stp-43201803 Results of current research Results of current research Results of current research Heliolatitude regularities of magnetically disturbed days with daily average geomagnetic index Dst<–100 nT Heliolatitude regularities of magnetically disturbed days with daily average geomagnetic index Dst<–100 nT Макаров Георгий Афанасьевич Makarov Georgy Afanasyevich gmakarov@ikfia.sbras.ru

кандидат физико-математических наук;

candidate of physical and mathematical sciences;

 Институт космофизических исследований и аэрономии им. Ю.Г. Шафера СО РАН Якутск Россия Yu.G. Shafer Institute of Cosmophysical Research and Aeronomy SB RAS Yakutsk Russian Federation 4 3 20 23 https://zh-szf.ru/en/nauka/article/23004/view

This paper considers storm days for a period 1966–2015 when the daily average geomagnetic Dst index was <–100 nT. The distribution of the number of days with a high daily average Dst is shown to depend on Earth’s heliolatitude φ: the number of days increases with the absolute value of φ in both solar hemispheres. It is found, as expected, that the seasonal distribution of storm days with Dst<–100 nT has equinoctial maxima. Moreover, there is a noticeable increase in the number of such days in July and November. It is noted that at Earth’s heliolatitudes 4.1°–5.0° there is a sharp increase in the number of storm days. It is established that this increase occurs during storm events in July and November, which stand out against the seasonal distribution of highly disturbed days.

This paper considers storm days for a period 1966–2015 when the daily average geomagnetic Dst index was <–100 nT. The distribution of the number of days with a high daily average Dst is shown to depend on Earth’s heliolatitude φ: the number of days increases with the absolute value of φ in both solar hemispheres. It is found, as expected, that the seasonal distribution of storm days with Dst<–100 nT has equinoctial maxima. Moreover, there is a noticeable increase in the number of such days in July and November. It is noted that at Earth’s heliolatitudes 4.1°–5.0° there is a sharp increase in the number of storm days. It is established that this increase occurs during storm events in July and November, which stand out against the seasonal distribution of highly disturbed days.

 geomagnetic Dst index geomagnetic storm seasonal variation of magnetic activity Earth’s heliolatitude geomagnetic Dst index geomagnetic storm seasonal variation of magnetic activity Earth’s heliolatitude

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