ULF waves observed during substorms in the solar wind and on the ground

Alimaganbetov, M.; Streltsov, A. V.

doi:10.1016/j.jastp.2018.10.007

Cited by 5 publications

(3 citation statements)

References 9 publications

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“…Outside of these limits, the spectrum was not considered. Those limits also correspond to what is usually called the ULF bandwidth, which is relevant to interplanetary shocks (Kajdič et al, ), to the study of sheaths (Kilpua et al, ), and to the interaction of the solar wind with the terrestrial magnetosphere (Alimaganbetov & Streltsov, ; Kepko et al, ; Osmane et al, ). One can also see, at the shock, approximately at 14:21, that every frequency presents a heightened

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Section: Method: Analysis Of a Single Eventmentioning

confidence: 86%

A Study of Fluctuations in Magnetic Cloud‐Driven Sheaths

2019

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Interplanetary coronal mass ejections are at the center of the research on geomagnetic activity. Sheaths, highly fluctuating structures, which can be found in front of fast interplanetary coronal mass ejections, are some of the least known geoeffective solar transients. Using Morlet transforms, we analyzed the magnetic fluctuations in a list of 42 well‐identified and isolated magnetic clouds driving a sheath and shock (Masías‐Meza et al., 2016, https://doi.org/10.1051/0004-6361/201628571. We studied the fluctuations inside sheaths by defining two quantities: the power and the anisotropy. With a simple statistical approach we found that sheaths, in particular, those driven by a fast magnetic cloud, encountering a highly turbulent solar wind, and forming a high Alfvén Mach number shock have high levels of turbulent energy (∼10 times compared with the solar wind) as well as a low anisotropy (approximately halved compared with the solar wind) of their fluctuations. On the other hand, the effect of the shock angle and plasma beta in the solar wind are less straightforward: If the shock is quasi‐parallel or the beta in the solar wind is high, both the turbulent energy in the sheaths and the anisotropy of the fluctuations are reduced; but for quasi‐perpendicular shocks or low beta solar wind the turbulent energy and anisotropy can take any value.

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Section: Method: Analysis Of a Single Eventmentioning

confidence: 86%

A Study of Fluctuations in Magnetic Cloud‐Driven Sheaths

2019

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“…For example, Horvath and Lovell (2021) show the correlation between surface waves on the plasmapause and Kelvin-Helmholtz waves in the solar wind in the magnetopause region, whereas Kepko and Spence (2003) suggest that the oscillations in the dynamic plasma pressure or the magnetic field carried by the solar wind can serve as a direct driver of the Earth's magnetosphere and produce electromagnetic waves with the frequency ≈1 mHz detected on the ground. Recent studies by Alimaganbetov and Streltsov (2018), 2020 support this hypothesis. These authors analyzed oscillations of the magnetic field detected by the ACE satellite in the solar wind and ground magnetometers at high (L = 5.76), middle (L = 2.46), and low (L = 1.87) latitudes during 84 intense substorms and found a good correlation between oscillations with frequencies less than 1 mHz observed in all these locations.…”

Section: Of 15mentioning

confidence: 90%

Feedback Interactions Between the Ionosphere and Magnetosphere at Middle Latitude

Alimaganbetov

Streltsov

2022

JGR Space Physics

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Ultra-low frequency (ULF) electromagnetic waves carry significant fluxes of the electromagnetic power, mass, and momentum in the highly coupled solar wind-magnetosphere-ionosphere system. Their role in the global energy exchange increases many times during magnetically active times like the geomagnetic storms and substorms. This is one of the main reasons why these waves and the associated field-aligned currents are extensively studied at high latitudes in connection with the discrete auroral arcs and other non-luminous phenomena.One of the most frequently considered mechanisms responsible for the generation of the large-amplitude ULF waves is the global magnetospheric field-line resonator (FLR) formed by the magnetic field line bounded by the conjugate locations in the ionosphere. Shear Alfvén waves can form a standing pattern between these locations. If there is an external or internal driver that provides power with a frequency matching one of the eigenfrequencies of the system, then the resonator can produce large-amplitude ULF waves. This idea had been proposed in classical papers by Cummings et al. (1969);Southwood (1974) and extensively studied after that, for example, Chen and Hasegawa (1974); Streltsov and Lotko (1995).The existence of the global magnetospheric resonator is strongly supported by the frequent observations obtained with ground magnetometers and radars, particularly, by these electromagnetic oscillations with discrete frequencies of 0.8, 1.3, 1.9, and 3.5 mHz in the night-side auroral zone (Fenrich et al., 1995;Samson, Harrold, et al., 1992). The same frequencies also have been detected in the field-aligned particle fluxes and luminosity of the discrete auroral arcs (Xu et al., 1993). The fact that at high altitudes these frequencies match the eigenfrequencies of the magnetic field lines stretched to the magnetotail (Lui & Cheng, 2001) provides a rationale to interpret them as a manifestation of the global field line resonator (Samson, Wallis, et al., 1992;Walker et al., 1992).FLR can be driven by several physical mechanisms. It can be a reconnection in the magnetotail (Angelopoulos et al., 2002), or the Kelvin-Helmholtz instabilities on the magnetopause or on the flanks of the magnetosphere in the so-called low-latitude boundary layers (Galinsky & Sonnerup, 1994;Marin et al., 2014). It can be energetic electron injections (Pilipenko et al., 2002) or feedback-active ionosphere-magnetosphere interactions driven by the electric field in the ionosphere (

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“…At the same time, a relationship has been found between Pi3 pulsation and variations of interplanetary medium parameters [Moiseev et al, 2016;Parkhomov et al, 2018]. Alimaganbetov and Streltsov [2018] have conducted a statistical analysis of wave disturbances in the solar wind (SW) during substorms. They have analyzed 75 intense substorms and found out that wave disturbances with 0.6-0.7 mHz frequencies often occur during substorms simultaneously in the magnetosphere and on Earth.…”

Section: Introductionmentioning

confidence: 99%

FEATURES OF EXCITATION AND AZIMUTHAL AND MERIDIONAL PROPAGATION OF LONG-PERIOD Pi3 OSCILLATIONS OF THE GEOMAGNETIC FIELD ON DECEMBER 8, 2017

Moiseev

Starodubtsev

Мишин

2020

Solar-Terrestrial Physics

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We study the Pi3 pulsations (with a period T=15–30 min) that were recorded on December 8, 2017 at ground stations in the midnight sector of the magnetosphere at the latitude range of DP2 current system convective electrojets. We have found that Pi3 are especially pronounced in the pre-midnight sector with amplitude of up to 300 nT and duration of up to 2.5 hrs. The pulsation amplitude rapidly decreased with decreasing latitude from F′=72° to F′=63°. The event was recorded during the steady magnetospheric convection. In the southward Bz component of the interplanetary magnetic field, irregular oscillations were detected in the Pi3 frequency range. They correspond to slow magnetosonic waves occurring without noticeable variations in the dynamic pressure Pd. Ground-based geomagnetic observations have shown azimuthal propagation of pulsations with a 0.6–10.6 km/s velocity east and west of the midnight meridian. An analysis of the dynamics of pulsations along the meridian has revealed their propagation to the equator at a velocity 0.75–7.87 km/s. In the projection onto the magnetosphere, the velocities are close in magnitude to the observed propagation velocities of substorm injected electrons. In the dawn-side magnetosphere during ground-observed Pi3 pulsations, compression mode oscillations were recorded. We conclude that propagation of geomagnetic field oscillations in this event depends on the dynamics of particle injections under the action of a large-scale electric field of magnetospheric convection, which causes the plasma to move to Earth due to reconnection in the magnetotail. Small-scale oscillations in the magnetosphere were secondary, excited by the solar wind oscillations penetrating into the magnetosphere.

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ULF waves observed during substorms in the solar wind and on the ground

Cited by 5 publications

References 9 publications

A Study of Fluctuations in Magnetic Cloud‐Driven Sheaths

A Study of Fluctuations in Magnetic Cloud‐Driven Sheaths

Feedback Interactions Between the Ionosphere and Magnetosphere at Middle Latitude

FEATURES OF EXCITATION AND AZIMUTHAL AND MERIDIONAL PROPAGATION OF LONG-PERIOD Pi3 OSCILLATIONS OF THE GEOMAGNETIC FIELD ON DECEMBER 8, 2017

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