Solar-Terrestrial Physics Solar-Terrestrial Physics Solar-Terrestrial Physics 2500-0535 20508 10.12737/stp-41201806 Results of current research Results of current research Results of current research Electron density at F1-layer heights in the last solar minimum (2007–2009) Electron density at F1-layer heights in the last solar minimum (2007–2009) Кушнаренко Галина Петровна Kushnarenko Galina Petrovna kusch@iszf.irk.ru

кандидат физико-математических наук;

candidate of physical and mathematical sciences;

 Яковлева Ольга Евгеньевна Yakovleva Olga Evgenyevna yakovleva@iszf.ru Кузнецова Галина Михайловна Kuznetsova Galina Mihaylovna kuz@iszf.irk.ru Институт солнечно-земной физики СО РАН Иркутск Россия Institute of Solar Terrestrial Physics SB RAS Irkutsk Russian Federation Институт солнечно-земной физики СО РАН Иркутск Россия Institute of Solar Terrestrial Physics SB RAS Irkutsk Russian Federation Институт солнечно-земной физики СО РАН Иркутск Россия Institute of Solar Terrestrial Physics SB RAS Irkutsk Russian Federation 4 1 61 63 https://naukaru.ru/en/nauka/article/20508/view

We present the results of the analysis of annual variations in daily electron density (N) at heights 140–160 km for the last solar minimum (2007–2009) obtained from digisonde measurements at the ionospheric station Irkutsk (52 °N, 104 °E). New coefficients of the known semi-empirical model (SEM) describing the connection between N and thermospheric characteristics are calculated to identify regularities of these variations. We have revealed that a characteristic feature of the annual N variations during the solar minimum is a change in their phase by 180° in a relatively narrow altitude interval (170–180 km). These results and the new SEM coefficients are original and important for atmospheric and ionospheric physics.

We present the results of the analysis of annual variations in daily electron density (N) at heights 140–160 km for the last solar minimum (2007–2009) obtained from digisonde measurements at the ionospheric station Irkutsk (52 °N, 104 °E). New coefficients of the known semi-empirical model (SEM) describing the connection between N and thermospheric characteristics are calculated to identify regularities of these variations. We have revealed that a characteristic feature of the annual N variations during the solar minimum is a change in their phase by 180° in a relatively narrow altitude interval (170–180 km). These results and the new SEM coefficients are original and important for atmospheric and ionospheric physics.

 semi-empirical model of electron density annual variations F1-layer heights semi-empirical model of electron density annual variations F1-layer heights

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