Direct Evidence for Electron Acceleration Within Ion‐Scale Flux Rope

Zhong, Zhihong; Zhou, Meng; Tang, Rongxin; Deng, Xiaohua; Turner, D. L.; Cohen, I. J.; Pang, Y.; Man, H. Y.; Russell, C. T.; Giles, B. L.; Paterson, W. R.; Khotyaintsev, Yuri V.; Burch, J. L.

doi:10.1029/2019gl085141

Cited by 51 publications

(89 citation statements)

References 70 publications

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“…In such a case, the long-term statistical characteristics of different electron PADs are very important dynamic properties of energetic electrons, which provide essential indicators to understand the physical processes of electron transport, energization, and loss (Liu et al, 2020;Ni, Zou, et al, 2016;Peng et al, 2020;Shi et al, 2016;Tang & Summers, 2019;H. Zhao et al, 2018;Zhong et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Statistical Characteristics of Electron Pitch Angle Distributions Inside the Magnetopasue Based on MMS Observations

Peng

Tang

et al. 2020

JGR Space Physics

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Electron pitch angle distributions (PADs) are very important to understand dynamics in the Earth's magnetosphere. Using observations of the Magnetospheric Multiscale (MMS) mission, we statistically investigate the characteristics of several types of electron PADs with energies of 200 eV to 2 keV (low energy) and 2-30 keV (energetic energy) inside the dayside magnetopause (L = 8 ∼ 13). For the low (energetic) energy level, the occurrence rates of pancake, flat-top, butterfly, isotropy, cigar, and rolling-pin distributions are as follows: 50.34% (45.20%), 17.92% (43.41%), 3.07% (7.28%), 4.34% (1.54%), 16.20% (1.20%), and 1.80% (0.06%), respectively. The pancake PAD is mainly located at lower L-shells with a maximum rate near the noonside, but other types of electron PADs occur at higher L-shells. In addition, the occurrence rate of the flat-top PAD is nearly the same for different magnetic local time. The butterfly and rolling-pin PADs occur in the afternoon side. The cigar PAD is mostly located in both the dawnside and duskside but is very scarce in the noonside. Furthermore, the relationships between these PADs and the solar wind dynamic pressure (P dyn) are studied. For low-energy electrons, the occurrence rate of the pancake distribution decreases, and that of the butterfly distribution increases with the enhancement of P dyn. However, for energetic energy level, the occurrence rate of the pancake (butterfly) PAD does not clearly decrease (increase) with the enhancement of P dyn at L ≤ 12. The statistical results reveal the important role of P dyn in electron dynamics inside the magnetopause.

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Section: Introductionmentioning

confidence: 99%

Statistical Characteristics of Electron Pitch Angle Distributions Inside the Magnetopasue Based on MMS Observations

Peng

Tang

et al. 2020

JGR Space Physics

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“…There exists varied and partially overlapping terminology for such coherent structures: flux ropes (as twisted flux bundles), plasmoids (as plasma packets), and magnetic islands (as topologically isolated structures). Following Zhong et al (2020), this commentary will focus on flux ropes. Flux ropes break up extended current sheets, enhancing the rate at which plasma and magnetic flux may be transported throughout the system.…”

Section: Mesoscale Reconnection Structurementioning

confidence: 99%

“…This constellation of four spacecraft flies in a close‐packed tetrahedron that achieves fine spatial resolution via interspacecraft spacing of less than 10 km and correspondingly high temporal resolution for electromagnetic fields (FIELDS, Torbert et al, 2016), distribution functions (FPI, Pollock et al, 2016), and energetic particles (FEEPS, Blake et al, 2016). These capabilities were crucial for the study of Zhong et al (2020), where the most energetic particles were observed for only a few seconds.…”

Section: Flux Ropes In the Earth's Magnetotailmentioning

confidence: 99%

“…A recent article by Zhong et al (2020) explores electron acceleration through a case study of a flux rope observed by Magnetospheric Multiscale Mission (MMS) in the Earth's magnetotail. This flux rope was (a) effectively isolated from the surrounding plasma and (b) sufficiently large and quiescent so that the electrons behaved adiabatically.…”

Section: Introductionmentioning

confidence: 99%

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Adiabatic Acceleration in a Magnetotail Flux Rope

Dahlin

2020

Geophysical Research Letters

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A new study of Magnetospheric Multiscale Mission (MMS) measurements in the Earth's magnetotail, presented by Zhong et al. (2020, https://doi.org/10.1029/2019GL085141) finds that enhanced energetic electrons in a reconnection‐generated ion‐scale flux rope in the magnetotail are due to the adiabatic processes of betatron and Fermi (curvature drift) acceleration. These mechanisms act, respectively, on the perpendicular and parallel components of the distribution function so that the role of these mechanisms may be distinctly identified. This study presents a useful template for studying in situ electron energization and contributes significantly to the ongoing discussion of the role of mesoscale structure in reconnection‐driven particle acceleration throughout the heliosphere.

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“…It is believed that MFRs are important in the mass, magnetic flux, and energy transport in geospace, for instance, an MFR is the prototype of the flux transfer event at the magnetopause (Russell & Elphic, 1978). An MFR is also suggested as a site for significant particle energization (Chen et al, 2008; Huang et al, 2012; Zhong et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Observations of Electron‐Only Magnetic Reconnection Associated With Macroscopic Magnetic Flux Ropes

Man

Zhou

et al. 2020

Geophysical Research Letters

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We report a Magnetospheric Multiscale (MMS) mission observation of magnetic reconnection occurring at the edge of a large-scale magnetic flux rope (MFR), the cross-section of which was about 2 R E. The MFR was observed at the duskside in the Earth's magnetotail and was highly oblique with its axis approximately along the X GSM direction. We find an electron-scale current sheet near the edge of this MFR. The Hall magnetic and electric field, super-Alfvénic electron outflow, parallel electric field, and positive energy dissipation were observed associated with the current sheet, which indicates that MMS detected a reconnecting current sheet with a large guide field. Interestingly, ions were not coupled in this reconnection, akin to the electron-only reconnection observed in the turbulent magnetosheath. We further find that the electron-only reconnection is commonly associated with a macroscopic MFR. This result will shed new light on understanding the multiscale coupling associated with an MFR in space plasmas.

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Direct Evidence for Electron Acceleration Within Ion‐Scale Flux Rope

Cited by 51 publications

References 70 publications

Statistical Characteristics of Electron Pitch Angle Distributions Inside the Magnetopasue Based on MMS Observations

Statistical Characteristics of Electron Pitch Angle Distributions Inside the Magnetopasue Based on MMS Observations

Adiabatic Acceleration in a Magnetotail Flux Rope

Observations of Electron‐Only Magnetic Reconnection Associated With Macroscopic Magnetic Flux Ropes

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