Kinetic structure of the sharp injection/dipolarization front in the flow‐braking region

Сергеев, В. А.; Angelopoulos, V.; Apatenkov, S.; Bonnell, J. W.; Ergun, R. E.; Nakamura, R.; McFadden, J. P.; Larson, D. E.

doi:10.1029/2009gl040658

Cited by 230 publications

(326 citation statements)

References 17 publications

Supporting

Mentioning

300

Contrasting

Unclassified

Order By: Relevance

“…All the equations are normalized using the following normalization quantities: L = 10 5 km, B 0 = 2 nT and E 0 = 40 mV m −1 (see Perri et al (2011) for more details). Further, the fluctuating potential decrease scale is set to = 8000 km (e.g., Nakamura et al, 2004;Perri et al, 2011); the amplitude of electromagnetic fluctuations, A 0 / , is of the order of 10 nT, which is consistent with observations (Borovsky et al, 1997); the dawn dusk electric field is E 0y = 0.2 mV m −1 ; the normal component of magnetic field is B n = 3 nT; and the asymptotic value of the magnetic field in the lobes is B max = 20 nT = 10 B 0 (Sergeev et al, 2003). The magnetic field B x (z) reaches its maximum (minimum) value for z = L z (z = −L z ), but most of the variation happens on scale λ.…”

Section: Numerical Simulationssupporting

confidence: 54%

“…In our numerical model, instead, only the He ++ ions exceed the 100 keV. This is probably due to the different acceleration mechanism: particles continuously interact with stochastic fluctuations and diffuse in the simulation box, and the perturbed magnetic field is at most 10 nT; conversely, in dipolarization fronts the peak magnetic field δB can be as large as 20-40 nT (Ono et al, 2009;Sergeev at al., 2009), and this is clearly influencing the acceleration rate.…”

Section: Energy Gainmentioning

confidence: 99%

“…A comparison with data from the Cluster spacecraft shows that different current sheet crossings can be well reproduced by the new solutions . Thus, it is interesting to understand influence of the new magnetic field profiles on the particle acceleration process for different ion species, also in view of the fact that the current sheet thickness and the current profiles are observed to change significantly during magnetospheric activity (Hoshino et al, 1996;Sergeev et al, 2003;Vasko et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Proton and heavy ion acceleration by stochastic fluctuations in the Earth's magnetotail

et al. 2016

View full text Add to dashboard Cite

Abstract. Spacecraft observations show that energetic ions are found in the Earth's magnetotail, with energies ranging from tens of keV to a few hundreds of keV. In this paper we carry out test particle simulations in which protons and other ion species are injected in the Vlasov magnetic field configurations obtained by Catapano et al. (2015). These configurations represent solutions of a generalized Harris model, which well describes the observed profiles in the magnetotail. In addition, three-dimensional time-dependent stochastic electromagnetic perturbations are included in the simulation box, so that the ion acceleration process is studied while varying the equilibrium magnetic field profile and the ion species. We find that proton energies of the order of 100 keV are reached with simulation parameters typical of the Earth's magnetotail. By changing the ion mass and charge, we can study the acceleration of heavy ions such as He ++ and O + , and it is found that energies of the order of 100-200 keV are reached in a few seconds for He ++ , and about 100 keV for O + .

show abstract

Section: Numerical Simulationssupporting

confidence: 54%

Section: Energy Gainmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Proton and heavy ion acceleration by stochastic fluctuations in the Earth's magnetotail

et al. 2016

View full text Add to dashboard Cite

show abstract

“…DFs are identified by a sharp increase of B z GSM and are associated with electron and ion acceleration [Asano et al, 2010;Zhou et al, 2010;Fu et al, 2011] as well as various wave activities, e.g., electron holes, whistler, lower hybrid, and electron cyclotron waves [Le Contel et al, 2009;Sergeev et al, 2009;Zhou et al, 2009;Deng et al, 2010;Khotyaintsev et al, 2011;Hwang et al, 2011].…”

Section: Introductionmentioning

confidence: 99%

Whistler mode waves at magnetotail dipolarization fronts

et al. 2014

View full text Add to dashboard Cite

We report the statistics of whistler mode waves observed in relation to dipolarization fronts (DFs) in Earth's magnetotail using data from the four Cluster spacecraft spanning a period of 9 years, 2001-2009. We show that whistler mode waves are common in a vicinity of DFs: between 30 and 60% of all DFs are associated with whistlers. Whistlers are about 7 times more likely to be observed near a DF than at any random location in the magnetotail. Therefore, whistlers are a characteristic signature of DFs. We find that whistlers are most often detected in the flux pileup region (FPR) following the DF, close to the center of the current sheet (B x ∼ 0) and in association with anisotropic electron distributions (T ⟂ > T ∥ ). This suggests that we typically observe emissions in the source region where they are generated by the anisotropic electrons produced by the betatron process inside the FPR.

show abstract

“…DFs are associated with electron and ion acceleration (e.g., Apatenkov et al, 2007;Asano et al, 2010;Zhou et al, 2010;Fu et al, 2011;Birn et al, 2011;Grigorenko et al, 2017) as well as with various wave activities, e.g., whistler emissions, lower hybrid and electron cyclotron waves (e.g., Le Contel et al, 2009;Zhou et al, 2009;Deng et al, 2010;Khotyaintsev et al, 2011;Hwang et al, 2011;Vilberg et al, 2014;Grigorenko et al, 2016). BBFs with embedded DFs transport energy and mass from a remote tail source to the near-Earth plasma sheet (PS), where the high-speed flows are slowed down and diverted (e.g., Sergeev et al, 2009;Ge et al, 2011 and references therein). This so-called flow braking region is located in the magnetotail approximately at X ∼ −10 R E (e.g., Shiokawa et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2018

View full text Add to dashboard Cite

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.

show abstract

Kinetic structure of the sharp injection/dipolarization front in the flow‐braking region

Cited by 230 publications

References 17 publications

Proton and heavy ion acceleration by stochastic fluctuations in the Earth's magnetotail

Proton and heavy ion acceleration by stochastic fluctuations in the Earth's magnetotail

Whistler mode waves at magnetotail dipolarization fronts

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

Contact Info

Product

Resources

About