Anharmonic oscillatory flow braking in the Earth's magnetotail

Panov, E. V.; Wolf, R. A.; Kubyshkina, M. V.; Nakamura, R.; Baumjohann, W.

doi:10.1002/2015gl064057

Cited by 12 publications

(16 citation statements)

References 34 publications

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“…Then, after 01:42 UT, and until the end of the dipolarization growth, the flow oscillations were observed by both P3 and C4. The similar phenomenon was discussed earlier in detail by e.g., Panov et al (2010Panov et al ( , 2015 in the context of the oscillatory flow braking through alternating field-aligned currents.…”

Section: Data Descriptionsupporting

confidence: 78%

Contrasting dynamics of electrons and protons in the near-Earth plasma sheet during dipolarization

et al. 2018

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Abstract. The fortunate location of Cluster and the THEMIS P3 probe in the near-Earth plasma sheet (PS) (at X ∼ −7-−9 R E ) allowed for the multipoint analysis of properties and spectra of electron and proton injections. The injections were observed during dipolarization and substorm current wedge formation associated with braking of multiple bursty bulk flows (BBFs). In the course of dipolarization, a gradual growth of the B Z magnetic field lasted ∼ 13 min and it was comprised of several B Z pulses or dipolarization fronts (DFs) with duration ≤ 1 min. Multipoint observations have shown that the beginning of the increase in suprathermal (> 50 keV) electron fluxes -the injection boundary -was observed in the PS simultaneously with the dipolarization onset and it propagated dawnward along with the onset-related DF. The subsequent dynamics of the energetic electron flux was similar to the dynamics of the magnetic field during the dipolarization. Namely, a gradual linear growth of the electron flux occurred simultaneously with the gradual growth of the B Z field, and it was comprised of multiple short (∼ few minutes) electron injections associated with the B Z pulses. This behavior can be explained by the combined action of local betatron acceleration at the B Z pulses and subsequent gradient drifts of electrons in the flux pile up region through the numerous braking and diverting DFs. The nonadiabatic features occasionally observed in the electron spectra during the injections can be due to the electron interactions with high-frequency electromagnetic or electrostatic fluctuations transiently observed in the course of dipolarization.On the contrary, proton injections were detected only in the vicinity of the strongest B Z pulses. The front thickness of these pulses was less than a gyroradius of thermal protons that ensured the nonadiabatic acceleration of protons. Indeed, during the injections in the energy spectra of protons the pronounced bulge was clearly observed in a finite energy range ∼ 70-90 keV. This feature can be explained by the nonadiabatic resonant acceleration of protons by the bursts of the dawn-dusk electric field associated with the B Z pulses.

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Section: Data Descriptionsupporting

confidence: 78%

Contrasting dynamics of electrons and protons in the near-Earth plasma sheet during dipolarization

et al. 2018

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“…After the dipolarization onset, two enhancements of positive V X were observed between 01:38 UT and 01:42 UT, indicating the arrival of BBFs at Cluster's location (see Figure e). Later, after 01:42 UT, the V X experienced negative and positive variations indicating oscillations of the flux tubes (e.g., Panov et al, , and references therein).…”

Section: Observationsmentioning

confidence: 99%

“…In the transition region (the so‐called flow braking region), where the stretched magnetotail‐like magnetic configuration transforms to a more dipole‐like shape (at X ~ −10 R E ), BBFs are decelerated and oscillate (e.g., Baumjohann, ; Panov et al, , ; Shiokawa et al, ). This results in the formation of a magnetic flux pileup region, perturbations of the near‐Earth PS, and a cross‐tail current through the development of various plasma instabilities (e.g., Grigorenko et al, ; Lui, ; Roux et al, , and references therein).…”

Section: Introductionmentioning

confidence: 99%

“…In the transition region (the so-called flow braking region), where the stretched magnetotail-like magnetic configuration transforms to a more dipole-like shape (at X~À10 R E ), BBFs are decelerated and oscillate (e.g., Baumjohann, 2002;Panov et al, 2010Panov et al, , 2015Shiokawa et al, 1997). This results in the formation of a magnetic flux pileup region, perturbations of the near-Earth PS, and a cross-tail current through the development of various plasma instabilities (e.g., Grigorenko et al, 2014;Lui, 2004;Roux et al, 1991 The origin of these pulses has been debated to be either the passage of spatial magnetic structures-DFs/dipolarizing flux bundles (DFBs) (e.g., Gabrielse et al, 2014Gabrielse et al, , 2017Liu et al, 2013Liu et al, , 2014Nakamura et al, 2013;Runov et al, 2011), which then pile up in the near-Earth PS and cause a prolonged dipolarization-or signatures of a near-Earth instability that leads to a global dipolarization (e.g., Lui, 2004).…”

Section: Introductionmentioning

confidence: 99%

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Intense Current Structures Observed at Electron Kinetic Scales in the Near‐Earth Magnetotail During Dipolarization and Substorm Current Wedge Formation

Григоренко

Dubyagin

Malykhin

et al. 2018

Geophysical Research Letters

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We use data from the 2013–2014 Cluster Inner Magnetosphere Campaign, with its uniquely small spacecraft separations (less than or equal to electron inertia length, λe), to study multiscale magnetic structures in 14 substorm‐related prolonged dipolarizations in the near‐Earth magnetotail. Three time scales of dipolarization are identified: (i) a prolonged growth of the BZ component with duration ≤20 min; (ii) BZ pulses with durations ≤1 min during the BZ growth; and (iii) strong magnetic field gradients with durations ≤2 s during the dipolarization growth. The values of these gradients observed at electron scales are several dozen times larger than the corresponding values of magnetic gradients simultaneously detected at ion scales. These nonlinear features in magnetic field gradients denote the formation of intense and localized (approximately a few λe) current structures during the dipolarization and substorm current wedge formation. These observations highlight the importance of electron scale processes in the formation of a 3‐D substorm current system.

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“…The presence of Pc pulsations in the region of dipolarization was also discussed in Panov et al (2013Panov et al ( , 2015.…”

mentioning

confidence: 99%

Turbulent Processes in the Earth's Magnetotail: Spectral and Statistical Research

Kozak¹,

Petrenko²,

Lui³

et al. 2018

Preprint

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Abstract. We use the ferroprobe measurements from four spacecraft of Cluster-2 mission (3 events from 2005 to 2015) for the analysis of turbulent processes in the Earth's magnetotail. For this study we conduct the spectral, wavelet and statistical analysis. In the framework of statistical examination, we determine the kurtosis for selected events and conduct extended selfsimilarity evaluation (analysis of distribution function moments of magnetic field fluctuations on different scales). We compare high order structure function of magnetic fluctuations during dipolarization with isotropic Kolmogorov and three-dimensional The wavelet analysis shows the presence of both direct and inverse cascade processes, which indicates the possibility of self-organization processes, as well as the presence of Pc pulsations. 15Copyright statement.

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Anharmonic oscillatory flow braking in the Earth's magnetotail

Cited by 12 publications

References 34 publications

Contrasting dynamics of electrons and protons in the near-Earth plasma sheet during dipolarization

Contrasting dynamics of electrons and protons in the near-Earth plasma sheet during dipolarization

Intense Current Structures Observed at Electron Kinetic Scales in the Near‐Earth Magnetotail During Dipolarization and Substorm Current Wedge Formation

Turbulent Processes in the Earth's Magnetotail: Spectral and Statistical Research

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