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Title: Electron diffusion region during magnetopause reconnection with an intermediate guide field: Magnetospheric multiscale observations: RECONNECTION ELECTRON DIFFUSION REGION

Authors:
ORCiD logo [1];  [2]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [3]; ORCiD logo [4]; ORCiD logo [1]; ORCiD logo [5]; ORCiD logo [2];  [6]; ORCiD logo [7];  [2]; ORCiD logo [2]; ORCiD logo [2]; ORCiD logo [8]; ORCiD logo [9]; ORCiD logo [9]; ORCiD logo [10]; ORCiD logo [11]; ORCiD logo [1]
  1. NASA, Goddard Space Flight Center, Greenbelt Maryland USA, Department of Astronomy, University of Maryland, College Park Maryland USA
  2. NASA, Goddard Space Flight Center, Greenbelt Maryland USA
  3. Laboratory of Atmospheric and Space Sciences, University of Colorado Boulder, Boulder Colorado USA
  4. Southwest Research Institute, San Antonio Texas USA
  5. Southwest Research Institute, San Antonio Texas USA, Department of Physics, University of New Hampshire, Durham New Hampshire USA
  6. Department of Physics and Astronomy, Rice University, Houston Texas USA
  7. Denali Scientific, Healy Alaska USA
  8. Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, Toulouse France, Centre National de la Recherche Scientifique, UMR 5277, Toulouse France
  9. Earth, Planetary, and Space Sciences, University of California, Los Angeles California USA
  10. Swedish Institute of Space Physics, Uppsala Sweden
  11. KTH Royal Institute of Technology, Stockholm Sweden
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1402346
Grant/Contract Number:
DESC0016278
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Journal of Geophysical Research. Space Physics
Additional Journal Information:
Journal Volume: 122; Journal Issue: 5; Related Information: CHORUS Timestamp: 2017-10-23 17:35:45; Journal ID: ISSN 2169-9380
Publisher:
Wiley Blackwell (John Wiley & Sons)
Country of Publication:
United States
Language:
English

Citation Formats

Chen, L. -J., Hesse, M., Wang, S., Gershman, D., Ergun, R. E., Burch, J., Bessho, N., Torbert, R. B., Giles, B., Webster, J., Pollock, C., Dorelli, J., Moore, T., Paterson, W., Lavraud, B., Strangeway, R., Russell, C., Khotyaintsev, Y., Lindqvist, P. -A., and Avanov, L. Electron diffusion region during magnetopause reconnection with an intermediate guide field: Magnetospheric multiscale observations: RECONNECTION ELECTRON DIFFUSION REGION. United States: N. p., 2017. Web. doi:10.1002/2017JA024004.
Chen, L. -J., Hesse, M., Wang, S., Gershman, D., Ergun, R. E., Burch, J., Bessho, N., Torbert, R. B., Giles, B., Webster, J., Pollock, C., Dorelli, J., Moore, T., Paterson, W., Lavraud, B., Strangeway, R., Russell, C., Khotyaintsev, Y., Lindqvist, P. -A., & Avanov, L. Electron diffusion region during magnetopause reconnection with an intermediate guide field: Magnetospheric multiscale observations: RECONNECTION ELECTRON DIFFUSION REGION. United States. doi:10.1002/2017JA024004.
Chen, L. -J., Hesse, M., Wang, S., Gershman, D., Ergun, R. E., Burch, J., Bessho, N., Torbert, R. B., Giles, B., Webster, J., Pollock, C., Dorelli, J., Moore, T., Paterson, W., Lavraud, B., Strangeway, R., Russell, C., Khotyaintsev, Y., Lindqvist, P. -A., and Avanov, L. Wed . "Electron diffusion region during magnetopause reconnection with an intermediate guide field: Magnetospheric multiscale observations: RECONNECTION ELECTRON DIFFUSION REGION". United States. doi:10.1002/2017JA024004.
@article{osti_1402346,
title = {Electron diffusion region during magnetopause reconnection with an intermediate guide field: Magnetospheric multiscale observations: RECONNECTION ELECTRON DIFFUSION REGION},
author = {Chen, L. -J. and Hesse, M. and Wang, S. and Gershman, D. and Ergun, R. E. and Burch, J. and Bessho, N. and Torbert, R. B. and Giles, B. and Webster, J. and Pollock, C. and Dorelli, J. and Moore, T. and Paterson, W. and Lavraud, B. and Strangeway, R. and Russell, C. and Khotyaintsev, Y. and Lindqvist, P. -A. and Avanov, L.},
abstractNote = {},
doi = {10.1002/2017JA024004},
journal = {Journal of Geophysical Research. Space Physics},
number = 5,
volume = 122,
place = {United States},
year = {Wed May 17 00:00:00 EDT 2017},
month = {Wed May 17 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1002/2017JA024004

Citation Metrics:
Cited by: 6works
Citation information provided by
Web of Science

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  • In situ measurements of magnetic reconnection in the Earth's magnetotail are presented showing that even a moderate guide field (20% of the reconnecting field) considerably distorts ion diffusion region structure. The Hall magnetic and electric fields are asymmetric and shunted away from the current sheet; an appropriately scaled particle-in-cell simulation is found to be in excellent agreement with the data. The results show the importance of correctly accounting for the effects of the magnetic shear when attempting to identify and study magnetic reconnection diffusion regions in nature.
  • Kinetic simulations of magnetic reconnection provide detailed information about the electric and magnetic structure throughout the simulation domain, as well as high resolution profiles of the essential fluid parameters including the electron and ion densities, flows, and pressure tensors. However, the electron distribution function, f(v), within the electron diffusion region becomes highly structured in the three dimensional velocity space and is not well resolved by the data available from the particle-in-cell (PIC) simulations. Here, we reconstruct the electron distribution function within the diffusion region at enhanced resolution. This is achieved by tracing electron orbits in the fields taken from PICmore » simulations back to the inflow region where an analytic form of the magnetized electron distribution is known. For antiparallel reconnection, the analysis reveals the highly structured nature of f(v), with striations corresponding to the number of times electrons have been reflected within the reconnection current layer, and exposes the origin of gradients in the electron pressure tensor important for momentum balance. The structure of the reconnection region is strongly tied to the pressure anisotropy that develops in the electrons upstream of the reconnection region. The addition of a guide field changes the nature of the electron distributions, and the differences are accounted for by studying the motion of single particles in the field geometry. Finally, the geometry of small guide field reconnection is shown to be highly sensitive to the ion/electron mass ratio applied in the simulation.« less
  • The Hall effect is suggested to be responsible for decoupling of electrons and ions in plasma during magnetic reconnection. It leads to redistribution of charged particles during magnetic reconnection. In this paper, charge distribution brought about by the Hall effect during magnetic reconnection is studied by using compressible Hall magnetohydrodynamics numerical simulation. Decoupling of electrons and ions in plasma can be clearly shown in this numerical simulation result. The bimodal structure of electron distribution in the electron diffusion region as well as its motion during magnetic reconnection have been found and discussed.
  • Particle-in-cell simulations of the guide field intermittent magnetic reconnection are performed to study electron acceleration and pitch angle distributions. During the growing stage of reconnection, the power-law distribution function for the high-energy electrons and the pitch angle distributions of the low-energy electrons are obtained and compare favorably with observations by the Wind spacecraft. Direct evidence is found for the secondary acceleration during the later reconnection stage. A correlation between the generation of energetic electrons and the induced reconnection electric field is found. Energetic electrons are accelerated first around the X line, and then in the region outside the diffusion region,more » when the reconnection electric field has a bipolar structure. The physical mechanisms of these accelerations are discussed. The in-plane electrostatic field that traps the low-energy electrons and causes the anisotropic pitch angle distributions has been observed.« less
  • The interactions between magnetic islands are considered to play an important role in electron acceleration during magnetic reconnection. In this paper, two-dimensional particle-in-cell simulations are performed to study electron acceleration during multiple X line reconnection with a guide field. Because the electrons remain almost magnetized, we can analyze the contributions of the parallel electric field, Fermi, and betatron mechanisms to electron acceleration during the evolution of magnetic reconnection through comparison with a guide-center theory. The results show that with the magnetic reconnection proceeding, two magnetic islands are formed in the simulation domain. Next, the electrons are accelerated by both themore » parallel electric field in the vicinity of the X lines and the Fermi mechanism due to the contraction of the two magnetic islands. Then, the two magnetic islands begin to merge into one, and, in such a process, the electrons can be accelerated by both the parallel electric field and betatron mechanisms. During the betatron acceleration, the electrons are locally accelerated in the regions where the magnetic field is piled up by the high-speed flow from the X line. At last, when the coalescence of the two islands into one big island finishes, the electrons can be further accelerated by the Fermi mechanism because of the contraction of the big island. With the increase of the guide field, the contributions of the Fermi and betatron mechanisms to electron acceleration become less and less important. When the guide field is sufficiently large, the contributions of the Fermi and betatron mechanisms are almost negligible.« less