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Title: Population Mixing in Asymmetric Magnetic Reconnection with a Guide Field

Authors:
; ; ; ;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1349706
Grant/Contract Number:
DESC0016278
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 118; Journal Issue: 14; Related Information: CHORUS Timestamp: 2017-04-03 22:18:54; Journal ID: ISSN 0031-9007
Publisher:
American Physical Society
Country of Publication:
United States
Language:
English

Citation Formats

Hesse, M., Chen, L. J., Liu, Y. -H., Bessho, N., and Burch, J. L. Population Mixing in Asymmetric Magnetic Reconnection with a Guide Field. United States: N. p., 2017. Web. doi:10.1103/PhysRevLett.118.145101.
Hesse, M., Chen, L. J., Liu, Y. -H., Bessho, N., & Burch, J. L. Population Mixing in Asymmetric Magnetic Reconnection with a Guide Field. United States. doi:10.1103/PhysRevLett.118.145101.
Hesse, M., Chen, L. J., Liu, Y. -H., Bessho, N., and Burch, J. L. Mon . "Population Mixing in Asymmetric Magnetic Reconnection with a Guide Field". United States. doi:10.1103/PhysRevLett.118.145101.
@article{osti_1349706,
title = {Population Mixing in Asymmetric Magnetic Reconnection with a Guide Field},
author = {Hesse, M. and Chen, L. J. and Liu, Y. -H. and Bessho, N. and Burch, J. L.},
abstractNote = {},
doi = {10.1103/PhysRevLett.118.145101},
journal = {Physical Review Letters},
number = 14,
volume = 118,
place = {United States},
year = {Mon Apr 03 00:00:00 EDT 2017},
month = {Mon Apr 03 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1103/PhysRevLett.118.145101

Citation Metrics:
Cited by: 1work
Citation information provided by
Web of Science

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  • We perform the first study of the properties of the Larmor electric field (LEF) in collisionless asymmetric magnetic reconnection in the presence of an out-of-plane (guide) magnetic field for different sets of representative upstream parameters at Earth’s dayside magnetopause with an ion temperature greater than the electron temperature (the ion-to-electron temperature ratio fixed at 2) using two-dimensional particle-in-cell simulations. We show that the LEF does persist in the presence of a guide field. We study how the LEF thickness and strength change as a function of guide field and the magnetospheric temperature and reconnecting magnetic field strength. We find thatmore » the thickness of the LEF structure decreases, while its magnitude increases when a guide field is added to the reconnecting magnetic field. The added guide field makes the Larmor radius smaller, so the scaling with the magnetospheric ion Larmor radius is similar to that reported for the case without a guide field. Note, however, that the physics causing the LEF is not well understood, so future work in other parameter regimes is needed to fully predict the LEF for arbitrary conditions. We also find that a previously reported upstream electron temperature anisotropy arises in the vicinity of the LEF region both with and without a guide field. We argue that the generation of the anisotropy is linked to the existence of the LEF. The LEF can be used in combination with the electron temperature anisotropy as a signature to effectively identify dayside reconnection sites in observations.« less
  • Magnetic reconnection occurring in collisionless environments is a multi-scale process involving both ion and electron kinetic processes. Because of their small mass, the electron scales are difficult to resolve in numerical and satellite data, it is therefore critical to know whether the overall evolution of the reconnection process is influenced by the kinetic nature of the electrons, or is unchanged when assuming a simpler, fluid, electron model. This paper investigates this issue in the general context of an asymmetric current sheet, where both the magnetic field amplitude and the density vary through the discontinuity. A comparison is made between fullymore » kinetic and hybrid kinetic simulations of magnetic reconnection in coplanar and guide field systems. The models share the initial condition but differ in their electron modeling. It is found that the overall evolution of the system, including the reconnection rate, is very similar between both models. The best agreement is found in the guide field system, which confines particle better than the coplanar one, where the locality of the moments is violated by the electron bounce motion. It is also shown that, contrary to the common understanding, reconnection is much faster in the guide field system than in the coplanar one. Both models show this tendency, indicating that the phenomenon is driven by ion kinetic effects and not electron ones.« less
  • Cited by 7
  • A combination of numerical simulation results and analytical theory is applied to the problem of magnetic reconnection in a guide magnetic field. An investigation of electron distribution functions within the electron diffusion region leads to a picture of mixing of particles with different acceleration histories on electron Larmor scales. Based on an apparent average loss of accelerated particles by field-aligned and ExB transport, it is proposed that the role of the reconnection electric field is to replenish this loss by acceleration of particles that enter the electron diffusion region. Analytic theory is employed to verify this model, and an equationmore » is derived, which balances the average electric field force density by a diffusion term applied to the electron momentum density. The diffusion coefficient contains explicitly the electron Larmor spatial scale and a poloidal transport time scale.« less