Period and damping factor of <i>P</i><i>i</i>2 pulsations during oscillatory flow braking in the magnetotail

Panov, E. V.; Baumjohann, W.; Nakamura, R.; Kubyshkina, M. V.; Glaßmeier, Karl‐Heinz; Angelopoulos, V.; Petrukovich, A. A.; Сергеев, В. А.

doi:10.1002/2013ja019633

Cited by 20 publications

(30 citation statements)

References 75 publications

(81 reference statements)

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“…Therefore, a flapping wave could transfer part of its energy for excitation of ULF waves that supplement other mechanisms of ULF wave generation by means of magnetotail dynamic processes (e.g. Runov et al, 2014;Panov et al, 2014). The connection between magnetotail dynamics and ionosphere processes involves the generation of parallel current systems in the near-Earth region.…”

Section: Discussionmentioning

confidence: 99%

Current sheet flapping in the near-Earth magnetotail: peculiarities of propagation and parallel currents

et al. 2016

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Abstract. We consider series of tilted current sheet crossings, corresponding to flapping waves in the near-Earth magnetotail. We analyse Cluster observations from 2005 to 2009, when spacecraft visited the magnetotail neutral plane near X ∈ [−17, −8], Y ∈ [−16, −2] R E (in the GSM system). Large separation of spacecraft allows us to estimate both local and global properties of flapping current sheets. We find significant variation in flapping wave direction of propagation between the middle tail and flanks. Th series of tilted current sheets represent the system of periodic, almost parallel currents with typical thickness of current filaments about L = 0.4 R E . The earthward gradients of B z magnetic field are reduced within this current system in comparison with the gradients in the quiet near-Earth magnetotail. The wavelength (i.e. a distance between two crossings of current sheets with the same orientations) of the flapping waves is larger than 2π L for most of observations. The velocity of flapping wave propagation is about ion bulk velocity and is significantly lower than the velocity of ion drift relative to electrons. We discuss possible drivers of flapping and estimate the amplitude of the total parallel current generated by flapping waves.

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Section: Discussionmentioning

confidence: 99%

Current sheet flapping in the near-Earth magnetotail: peculiarities of propagation and parallel currents

et al. 2016

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“…These facts make it difficult to use plasma sheet velocity measurements to test whether the oscillations are harmonic. However, the statistically established fact that the signal from the oscillatory braking of fast flows in the near-Earth plasma sheet is transmitted down to Earth and is observed as Pi2 pulsations there [Panov et al, 2014b] allowed us to use ground magnetometer measurements near THEMIS footprints instead, thereby suggesting anharmonicity of the flow oscillations observed by THEMIS probes P1-P3 at 11-14 R E downtail.…”

Section: Discussionmentioning

confidence: 99%

“…The oscillatory braking of fast flows in the near-Earth plasma sheet is transmitted down to Earth and observed as Pi2 pulsations [Panov et al, 2014b]. With the help of the AM03 model, we identified the location of THEMIS probes' footprints to be between Rankin Inlet and Gillam/Fort Churchill, Canada [Panov et al, 2014a].…”

Section: Themis Observations and Theoretical Expectationsmentioning

confidence: 99%

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Anharmonic oscillatory flow braking in the Earth's magnetotail

Panov

Wolf

Kubyshkina

et al. 2015

Geophysical Research Letters

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Plasma sheet bursty bulk flows often oscillate around their equilibrium position at about 10 RE downtail. The radial magnetic field, pressure, and flux tube volume profiles usually behave differently earthward and tailward of this position. Using data from five Time History of Events and Macroscale Interactions during Substorms (THEMIS) probes, we reconstruct these profiles with the help of an empirical model and apply thin filament theory to show that the oscillatory flow braking can occur in an asymmetric potential. Thus, the thin filament oscillations appear to be anharmonic, with a power spectrum exhibiting peaks at both the fundamental frequency and the first harmonic. Such anharmonic oscillatory braking can explain the presence of the first harmonic in Pi2 pulsations (frequency doubling), which are simultaneously observed by magnetometers on the ground near the conjugate THEMIS footprints.

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“…Flow bursts have often been treated as moving earthward and stopping within the plasma sheet, as has been seen in the MHD simulations of Birn and Hesse [] and Birn et al []. There is also a proposal that flow bursts oscillate back and forth in radial distance as they stop within the near‐Earth plasma sheet [ Wolf et al , ], and this proposal has been supported by oscillatory flows observed in the plasma sheet by Panov et al [, ].…”

Section: Introductionmentioning

confidence: 96%

Azimuthal flow bursts in the inner plasma sheet and possible connection with SAPS and plasma sheet earthward flow bursts

et al. 2015

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We have combined radar observations and auroral images obtained during the Poker Flat Incoherent Scatter Radar Ion Neutral Observations in the Thermosphere campaign to show the common occurrence of westward moving, localized auroral brightenings near the auroral equatorward boundary and to show their association with azimuthally moving flow bursts near or within the subauroral polarization stream (SAPS) region. These results indicate that the SAPS region, rather than consisting of relatively stable proton precipitation and westward flows, can have rapidly varying flows, with speeds varying from ~100 m/s to ~1 km/s in just a few minutes. The auroral brightenings are associated with bursts of weak electron precipitation that move westward with the westward flow bursts and extend into the SAPS region. Additionally, our observations show evidence that the azimuthally moving flow bursts often connect to earthward (equatorward in the ionosphere) plasma sheet flow bursts. This indicates that rather than stopping or bouncing, some flow bursts turn azimuthally after reaching the inner plasma sheet and lead to the bursts of strong azimuthal flow. Evidence is also seen for a general guiding of the flow bursts by the large‐scale convection pattern, flow bursts within the duskside convection being azimuthally turned to the west, and those within the dawn cell being turned toward the east. The possibility that the SAPS region flow structures considered here may be connected to localized flow enhancements from the polar cap that cross the nightside auroral poleward boundary and lead to flow bursts within the plasma sheet warrants further consideration.

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Period and damping factor of Pi2 pulsations during oscillatory flow braking in the magnetotail

Cited by 20 publications

References 75 publications

Current sheet flapping in the near-Earth magnetotail: peculiarities of propagation and parallel currents

Current sheet flapping in the near-Earth magnetotail: peculiarities of propagation and parallel currents

Anharmonic oscillatory flow braking in the Earth's magnetotail

Azimuthal flow bursts in the inner plasma sheet and possible connection with SAPS and plasma sheet earthward flow bursts

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