Properties and Acceleration Mechanisms of Electrons Up To 200 keV Associated With a Flux Rope Pair and Reconnection X‐Lines Around It in Earth's Plasma Sheet

Weijie Sun; Drew L. Turner; Qile Zhang; Shan Wang; Jan Egedal; Trevor Leonard; James A. Slavin; Qiang Hu; Ian J. Cohen; Kevin Genestreti; Gangkai Poh; Daniel J. Gershman; Andrew Smith; Guan Le; Rumi Nakamura; Barbara L. Giles; Robert E. Ergun; James L. Burch

doi:10.1029/2022ja030721

Properties and Acceleration Mechanisms of Electrons Up To 200 keV Associated With a Flux Rope Pair and Reconnection X‐Lines Around It in Earth's Plasma Sheet

Weijie Sun^*, Drew L. Turner, Qile Zhang, Shan Wang, Jan Egedal, Trevor Leonard, James A. Slavin, Qiang Hu, Ian J. Cohen, Kevin Genestreti, Gangkai Poh, Daniel J. Gershman, Andrew Smith, Guan Le, Rumi Nakamura, Barbara L. Giles, Robert E. Ergun, James L. Burch

^*Corresponding author for this work

Mathematics, Physics and Electrical Engineering

Research output: Contribution to journal › Article › peer-review

4 Citations (Scopus)

23 Downloads (Pure)

Abstract

The properties and acceleration mechanisms of electrons (<200 keV) associated with a pair of tailward traveling flux ropes and accompanied reconnection X-lines in Earth's plasma sheet are investigated with MMS measurements. Energetic electrons are enhanced on both boundaries and core of the flux ropes. The power-law spectra of energetic electrons near the X-lines and in flux ropes are harder than those on flux rope boundaries. Theoretical calculations show that the highest energy of adiabatic electrons is a few keV around the X-lines, tens of keV immediately downstream of the X-lines, hundreds of keV on the flux rope boundaries, and a few MeV in the flux rope cores. The X-lines cause strong energy dissipation, which may generate the energetic electron beams around them. The enhanced electron parallel temperature can be caused by the curvature-driven Fermi acceleration and the parallel electric potential. Betatron acceleration due to the magnetic field compression is strong on flux rope boundaries, which enhances energetic electrons in the perpendicular direction. Electrons can be trapped between the flux rope pair due to mirror force and parallel electric potential. Electrostatic structures in the flux rope cores correspond to potential drops up to half of the electron temperature. The energetic electrons and the electron distribution functions in the flux rope cores are suggested to be transported from other dawn-dusk directions, which is a 3-dimensional effect. The acceleration and deceleration of the Betatron and Fermi processes appear alternately indicating that the magnetic field and plasma are turbulent around the flux ropes.

Original language	English
Article number	e2022JA030721
Number of pages	28
Journal	Journal of Geophysical Research: Space Physics
Volume	127
Issue number	12
Early online date	23 Dec 2022
DOIs	https://doi.org/10.1029/2022ja030721 https://doi.org/10.1029/2022JA030721
Publication status	Published - Dec 2022

Keywords

Betatron and Fermi acceleration
adiabatic energy
reconnection X-line
flux rope
energetic electrons

Access to Document

10.1029/2022ja030721Licence: CC BY
10.1029/2022JA030721

JGR Space Physics - 2022 - Sun - Properties and Acceleration Mechanisms of Electrons Up To 200 keV Associated With a FluxFinal published version, 5.62 MBLicence: CC BY

Cite this

Sun, W., Turner, D. L., Zhang, Q., Wang, S., Egedal, J., Leonard, T., Slavin, J. A., Hu, Q., Cohen, I. J., Genestreti, K., Poh, G., Gershman, D. J., Smith, A., Le, G., Nakamura, R., Giles, B. L., Ergun, R. E., & Burch, J. L. (2022). Properties and Acceleration Mechanisms of Electrons Up To 200 keV Associated With a Flux Rope Pair and Reconnection X‐Lines Around It in Earth's Plasma Sheet. Journal of Geophysical Research: Space Physics, 127(12), Article e2022JA030721. https://doi.org/10.1029/2022ja030721, https://doi.org/10.1029/2022JA030721

@article{8bfd6e072a6248f5b790962701eff735,

title = "Properties and Acceleration Mechanisms of Electrons Up To 200 keV Associated With a Flux Rope Pair and Reconnection X‐Lines Around It in Earth's Plasma Sheet",

abstract = "The properties and acceleration mechanisms of electrons (<200 keV) associated with a pair of tailward traveling flux ropes and accompanied reconnection X-lines in Earth's plasma sheet are investigated with MMS measurements. Energetic electrons are enhanced on both boundaries and core of the flux ropes. The power-law spectra of energetic electrons near the X-lines and in flux ropes are harder than those on flux rope boundaries. Theoretical calculations show that the highest energy of adiabatic electrons is a few keV around the X-lines, tens of keV immediately downstream of the X-lines, hundreds of keV on the flux rope boundaries, and a few MeV in the flux rope cores. The X-lines cause strong energy dissipation, which may generate the energetic electron beams around them. The enhanced electron parallel temperature can be caused by the curvature-driven Fermi acceleration and the parallel electric potential. Betatron acceleration due to the magnetic field compression is strong on flux rope boundaries, which enhances energetic electrons in the perpendicular direction. Electrons can be trapped between the flux rope pair due to mirror force and parallel electric potential. Electrostatic structures in the flux rope cores correspond to potential drops up to half of the electron temperature. The energetic electrons and the electron distribution functions in the flux rope cores are suggested to be transported from other dawn-dusk directions, which is a 3-dimensional effect. The acceleration and deceleration of the Betatron and Fermi processes appear alternately indicating that the magnetic field and plasma are turbulent around the flux ropes.",

keywords = "Betatron and Fermi acceleration, adiabatic energy, reconnection X-line, flux rope, energetic electrons",

author = "Weijie Sun and Turner, {Drew L.} and Qile Zhang and Shan Wang and Jan Egedal and Trevor Leonard and Slavin, {James A.} and Qiang Hu and Cohen, {Ian J.} and Kevin Genestreti and Gangkai Poh and Gershman, {Daniel J.} and Andrew Smith and Guan Le and Rumi Nakamura and Giles, {Barbara L.} and Ergun, {Robert E.} and Burch, {James L.}",

note = "Funding Information: This work at the University of Michigan‐Ann Arbor (Weijie Sun, James A. Slavin) is supported by NASA Grants 80NSSC21K0517 and 80NSSC20K1014. This work at the University of Alabama in Huntsville (Qiang Hu) is supported by NASA Grant 80NSSC21K0003. This work at the Los Alamos National Laboratory (Qile Zhang) is supported by NASA Grant 80HQTR21T0103. This research was supported by the NASA MMS in association with NASA contract NNG04EB99C at Southwest Research Institute (SwRI). Institut de Recherche en Astrophysique et Plan{\'e}tologie (IRAP) contributions to MMS FPI were supported by Centre National d'{\'E}tudes Spatiales (CNES) and Centre National de la Recherche Scientifique (CNRS).We thank the MMS team for data access and support. Weijie Sun thanks Jia Huang (Space Sciences Laboratory, University of California, Berkeley), Ruilong Guo (Shandong University, Weihai), Anmin Tian (Shandong University, Weihai), and Barry H Mauk (Johns Hopkins Applied Physics Laboratory) for the helpful discussions.",

year = "2022",

month = dec,

doi = "10.1029/2022ja030721",

language = "English",

volume = "127",

journal = "Journal of Geophysical Research: Space Physics",

issn = "2169-9380",

publisher = "American Geophysical Union",

number = "12",

}

Sun, W, Turner, DL, Zhang, Q, Wang, S, Egedal, J, Leonard, T, Slavin, JA, Hu, Q, Cohen, IJ, Genestreti, K, Poh, G, Gershman, DJ, Smith, A, Le, G, Nakamura, R, Giles, BL, Ergun, RE & Burch, JL 2022, 'Properties and Acceleration Mechanisms of Electrons Up To 200 keV Associated With a Flux Rope Pair and Reconnection X‐Lines Around It in Earth's Plasma Sheet', Journal of Geophysical Research: Space Physics, vol. 127, no. 12, e2022JA030721. https://doi.org/10.1029/2022ja030721, https://doi.org/10.1029/2022JA030721

Properties and Acceleration Mechanisms of Electrons Up To 200 keV Associated With a Flux Rope Pair and Reconnection X‐Lines Around It in Earth's Plasma Sheet. / Sun, Weijie; Turner, Drew L.; Zhang, Qile et al.
In: Journal of Geophysical Research: Space Physics, Vol. 127, No. 12, e2022JA030721, 12.2022.

Research output: Contribution to journal › Article › peer-review

TY - JOUR

T1 - Properties and Acceleration Mechanisms of Electrons Up To 200 keV Associated With a Flux Rope Pair and Reconnection X‐Lines Around It in Earth's Plasma Sheet

AU - Sun, Weijie

AU - Turner, Drew L.

AU - Zhang, Qile

AU - Wang, Shan

AU - Egedal, Jan

AU - Leonard, Trevor

AU - Slavin, James A.

AU - Hu, Qiang

AU - Cohen, Ian J.

AU - Genestreti, Kevin

AU - Poh, Gangkai

AU - Gershman, Daniel J.

AU - Smith, Andrew

AU - Le, Guan

AU - Nakamura, Rumi

AU - Giles, Barbara L.

AU - Ergun, Robert E.

AU - Burch, James L.

N1 - Funding Information: This work at the University of Michigan‐Ann Arbor (Weijie Sun, James A. Slavin) is supported by NASA Grants 80NSSC21K0517 and 80NSSC20K1014. This work at the University of Alabama in Huntsville (Qiang Hu) is supported by NASA Grant 80NSSC21K0003. This work at the Los Alamos National Laboratory (Qile Zhang) is supported by NASA Grant 80HQTR21T0103. This research was supported by the NASA MMS in association with NASA contract NNG04EB99C at Southwest Research Institute (SwRI). Institut de Recherche en Astrophysique et Planétologie (IRAP) contributions to MMS FPI were supported by Centre National d'Études Spatiales (CNES) and Centre National de la Recherche Scientifique (CNRS).We thank the MMS team for data access and support. Weijie Sun thanks Jia Huang (Space Sciences Laboratory, University of California, Berkeley), Ruilong Guo (Shandong University, Weihai), Anmin Tian (Shandong University, Weihai), and Barry H Mauk (Johns Hopkins Applied Physics Laboratory) for the helpful discussions.

PY - 2022/12

Y1 - 2022/12

N2 - The properties and acceleration mechanisms of electrons (<200 keV) associated with a pair of tailward traveling flux ropes and accompanied reconnection X-lines in Earth's plasma sheet are investigated with MMS measurements. Energetic electrons are enhanced on both boundaries and core of the flux ropes. The power-law spectra of energetic electrons near the X-lines and in flux ropes are harder than those on flux rope boundaries. Theoretical calculations show that the highest energy of adiabatic electrons is a few keV around the X-lines, tens of keV immediately downstream of the X-lines, hundreds of keV on the flux rope boundaries, and a few MeV in the flux rope cores. The X-lines cause strong energy dissipation, which may generate the energetic electron beams around them. The enhanced electron parallel temperature can be caused by the curvature-driven Fermi acceleration and the parallel electric potential. Betatron acceleration due to the magnetic field compression is strong on flux rope boundaries, which enhances energetic electrons in the perpendicular direction. Electrons can be trapped between the flux rope pair due to mirror force and parallel electric potential. Electrostatic structures in the flux rope cores correspond to potential drops up to half of the electron temperature. The energetic electrons and the electron distribution functions in the flux rope cores are suggested to be transported from other dawn-dusk directions, which is a 3-dimensional effect. The acceleration and deceleration of the Betatron and Fermi processes appear alternately indicating that the magnetic field and plasma are turbulent around the flux ropes.

AB - The properties and acceleration mechanisms of electrons (<200 keV) associated with a pair of tailward traveling flux ropes and accompanied reconnection X-lines in Earth's plasma sheet are investigated with MMS measurements. Energetic electrons are enhanced on both boundaries and core of the flux ropes. The power-law spectra of energetic electrons near the X-lines and in flux ropes are harder than those on flux rope boundaries. Theoretical calculations show that the highest energy of adiabatic electrons is a few keV around the X-lines, tens of keV immediately downstream of the X-lines, hundreds of keV on the flux rope boundaries, and a few MeV in the flux rope cores. The X-lines cause strong energy dissipation, which may generate the energetic electron beams around them. The enhanced electron parallel temperature can be caused by the curvature-driven Fermi acceleration and the parallel electric potential. Betatron acceleration due to the magnetic field compression is strong on flux rope boundaries, which enhances energetic electrons in the perpendicular direction. Electrons can be trapped between the flux rope pair due to mirror force and parallel electric potential. Electrostatic structures in the flux rope cores correspond to potential drops up to half of the electron temperature. The energetic electrons and the electron distribution functions in the flux rope cores are suggested to be transported from other dawn-dusk directions, which is a 3-dimensional effect. The acceleration and deceleration of the Betatron and Fermi processes appear alternately indicating that the magnetic field and plasma are turbulent around the flux ropes.

KW - Betatron and Fermi acceleration

KW - adiabatic energy

KW - reconnection X-line

KW - flux rope

KW - energetic electrons

UR - http://www.scopus.com/inward/record.url?scp=85146079192&partnerID=8YFLogxK

U2 - 10.1029/2022ja030721

DO - 10.1029/2022ja030721

M3 - Article

SN - 2169-9380

VL - 127

JO - Journal of Geophysical Research: Space Physics

JF - Journal of Geophysical Research: Space Physics

IS - 12

M1 - e2022JA030721

ER -

Properties and Acceleration Mechanisms of Electrons Up To 200 keV Associated With a Flux Rope Pair and Reconnection X‐Lines Around It in Earth's Plasma Sheet

Abstract

Keywords

Access to Document

Other files and links

Fingerprint

Cite this