Solar-Terrestrial Physics Solar-Terrestrial Physics Solar-Terrestrial Physics 2500-0535 100192 10.12737/stp-112202505 Results of current research Results of current research Results of current research Satellite and ground-based observations of Pc1 pulsations during a magnetic storm in March 2023 Satellite and ground-based observations of Pc1 pulsations during a magnetic storm in March 2023 Позднякова Дарья Дмитриевна Pozdnyakova Daria Dmitrievna d_pozdnyakova@live.ru https://orcid.org/0000-0003-3056-7465 Пилипенко Вячеслав Анатольевич Pilipenko Vyacheslav Anatolievich space.soliton@gmail.com

доктор физико-математических наук;

doctor of physical and mathematical sciences;

 Носэ Масахито Nose Masahito nose.masahito@gmail.com Хомутов Сергей Юрьевич Khomutov Sergey Yuryevich hom@ngs.ru

кандидат физико-математических наук;

candidate of physical and mathematical sciences;

 Баишев Дмитрий Гаврильевич Baishev Dmitry Gavrilyevich baishev@ikfia.ysn.ru

кандидат физико-математических наук;

candidate of physical and mathematical sciences;

 Институт физики Земли им. О.Ю. Шмидта РАН Москва Россия Schmidt Institute of Physics of the Earth RAS Moscow Russian Federation Институт физики Земли им. О.Ю. Шмидта РАН Москва Россия Schmidt Institute of Physics of the Earth RAS Moscow Russian Federation Геофизический центр РАН Москва Россия Geophysical Center RAS Moscow Russian Federation Институт космических исследований Москва Россия Space Research Institute Moscow Russian Federation Нагойский городской университет Нагоя Япония Нагойский городской университет Nagoya Japan Институт космофизических исследований и распространения радиоволн ДВО РАН Паратунка Россия Institute of Cosmophysical Research and Radio Wave Propagation FEB RAS Paratunka Russian Federation 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 26 06 2025 26 06 2025 11 2 48 59 11 12 2024 03 03 2025 https://zh-szf.ru/en/nauka/article/100192/view

We have analyzed electromagnetic ion-cyclotron oscillations of the Pc1 range (~1 Hz) recorded during the recovery phase of the March 25, 2023 magnetic storm at the network of ground stations in the Far East and at low-orbit SWARM satellites passing over the stations. The collected data made it possible to trace propagation of Pc1 waves through the ionosphere to Earth’s surface and along the ionosphere. While long-term (~1 hour) narrowband pulsations were observed at ground stations, satellites recorded only a short (~40 s) burst of transverse oscillations. Estimated coherence of signals between close SWARM-A and -C satellites, separated by ~1° longitude, gives a transverse scale of the wave packet in the ionosphere equal to ~90 km. The long duration of pulsations at ground stations is caused by waveguide propagation of signals along the ionosphere due to which the station “collects” signals from a large magnetospheric region. The presence of waveguide propagation is confirmed by the orientation of the polarization ellipse of ground-based Pc1 pulsations relative to the site of injection of waves into the ionosphere. It is hypothesized that ion-cyclotron instability develops in the form of localized and short-lived bursts, but the mechanism of such a regime remains unclear.

We have analyzed electromagnetic ion-cyclotron oscillations of the Pc1 range (~1 Hz) recorded during the recovery phase of the March 25, 2023 magnetic storm at the network of ground stations in the Far East and at low-orbit SWARM satellites passing over the stations. The collected data made it possible to trace propagation of Pc1 waves through the ionosphere to Earth’s surface and along the ionosphere. While long-term (~1 hour) narrowband pulsations were observed at ground stations, satellites recorded only a short (~40 s) burst of transverse oscillations. Estimated coherence of signals between close SWARM-A and -C satellites, separated by ~1° longitude, gives a transverse scale of the wave packet in the ionosphere equal to ~90 km. The long duration of pulsations at ground stations is caused by waveguide propagation of signals along the ionosphere due to which the station “collects” signals from a large magnetospheric region. The presence of waveguide propagation is confirmed by the orientation of the polarization ellipse of ground-based Pc1 pulsations relative to the site of injection of waves into the ionosphere. It is hypothesized that ion-cyclotron instability develops in the form of localized and short-lived bursts, but the mechanism of such a regime remains unclear.

 Pc1 pulsations electromagnetic ion-cyclotron waves SWARM satellites Pc1 pulsations electromagnetic ion-cyclotron waves SWARM satellites The work was financially supported by RSF Grant No. 24-77-10012 The work was financially supported by RSF Grant No. 24-77-10012

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