Solar-Terrestrial Physics Solar-Terrestrial Physics Solar-Terrestrial Physics 2500-0535 109237 10.12737/stp-114202513 20TH ANNUAL CONFERENCE “PLASMA PHYSICS IN THE SOLAR SYSTEM”. FEBRUARY 10–14, 2025, SPACE RESEARCH INSTITUTE RAS, MOSCOW, RUSSIA 20TH ANNUAL CONFERENCE “PLASMA PHYSICS IN THE SOLAR SYSTEM”. FEBRUARY 10–14, 2025, SPACE RESEARCH INSTITUTE RAS, MOSCOW, RUSSIA 20TH ANNUAL CONFERENCE “PLASMA PHYSICS IN THE SOLAR SYSTEM”. FEBRUARY 10–14, 2025, SPACE RESEARCH INSTITUTE RAS, MOSCOW, RUSSIA Coherence time scales of long-period ULF variations of magnetic field in vicinity of the night-side magnetopause Coherence time scales of long-period ULF variations of magnetic field in vicinity of the night-side magnetopause Стуков Данила Алексеевич Stukov Danila Alekseevich sda@ifz.ru https://orcid.org/0000-0003-0678-8743 Ягова Надежда Викторовна Yagova Nadezda Viktorovna nyagova@ifz.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 солнечно-земной физики СО РАН Иркутск Россия Institute of Solar-Terrestrial Physics SB RAS Irkutsk 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 of the Russian Academy of Sciences Moscow Russian Federation 10 12 2025 10 12 2025 11 4 120 129 03 04 2025 06 08 2025 https://zh-szf.ru/en/nauka/article/109237/view

We examine magnetic field variations within the frequency range of several millihertz (Pc5-6/Pi3 geomagnetic pulsations) in the near-Earth magnetotail and adjacent flank magnetosheath regions, using data from Cluster satellites for 2016. Dependence of spectral coherence on interval length is analyzed for a satellite pair Cluster-1 and Cluster-4 at different satellite positions relative to the magnetopause. It is shown that absolute coherence and the rate of its decline with increasing time interval length differ for the longitudinal and transverse magnetic field components, as well as for different satellite positions. We also present a case study of a coherent pulsation recorded in the magnetosheath at low solar wind velocity and weak fluctuations in front of the bow shock.

We examine magnetic field variations within the frequency range of several millihertz (Pc5-6/Pi3 geomagnetic pulsations) in the near-Earth magnetotail and adjacent flank magnetosheath regions, using data from Cluster satellites for 2016. Dependence of spectral coherence on interval length is analyzed for a satellite pair Cluster-1 and Cluster-4 at different satellite positions relative to the magnetopause. It is shown that absolute coherence and the rate of its decline with increasing time interval length differ for the longitudinal and transverse magnetic field components, as well as for different satellite positions. We also present a case study of a coherent pulsation recorded in the magnetosheath at low solar wind velocity and weak fluctuations in front of the bow shock.

 Pc5-6/Pi3 geomagnetic pulsations magnetotail magnetopause magnetosheath coherence Pc5-6/Pi3 geomagnetic pulsations magnetotail magnetopause magnetosheath coherence The work was financially supported by the Russian Foundation for Basic Research (Project No. 24-77-10012) The work was financially supported by the Russian Foundation for Basic Research (Project No. 24-77-10012)

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