Inverse energy dispersion of energetic ions observed in the magnetosheath

Abstract We present a case study of energetic ions observed by the Energetic Particle Detector (EPD) on the Magnetospheric Multiscale spacecraft in the magnetosheath just outside the subsolar magnetopause that occurred at 1000 UT on 8 December 2015. As the magnetopause receded inward, the EPD observ...

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Main Authors: S. H. Lee, D. G. Sibeck, K.‐J. Hwang, Y. Wang, M. V. D. Silveira, M.‐C. Fok, B. H. Mauk, I. J. Cohen, J. M. Ruohoniemi, N. Kitamura, J. L. Burch, B. L. Giles, R. B. Torbert, C. T. Russell, M. Lester
Format: Article
Language:English
Published: Wiley 2016-07-01
Series:Geophysical Research Letters
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Online Access:https://doi.org/10.1002/2016GL069840
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author S. H. Lee
D. G. Sibeck
K.‐J. Hwang
Y. Wang
M. V. D. Silveira
M.‐C. Fok
B. H. Mauk
I. J. Cohen
J. M. Ruohoniemi
N. Kitamura
J. L. Burch
B. L. Giles
R. B. Torbert
C. T. Russell
M. Lester
author_facet S. H. Lee
D. G. Sibeck
K.‐J. Hwang
Y. Wang
M. V. D. Silveira
M.‐C. Fok
B. H. Mauk
I. J. Cohen
J. M. Ruohoniemi
N. Kitamura
J. L. Burch
B. L. Giles
R. B. Torbert
C. T. Russell
M. Lester
author_sort S. H. Lee
collection DOAJ
description Abstract We present a case study of energetic ions observed by the Energetic Particle Detector (EPD) on the Magnetospheric Multiscale spacecraft in the magnetosheath just outside the subsolar magnetopause that occurred at 1000 UT on 8 December 2015. As the magnetopause receded inward, the EPD observed a burst of energetic (∼50–1000 keV) proton, helium, and oxygen ions that exhibited an inverse dispersion, with the lowest energy ions appearing first. The prolonged interval of fast antisunward flow observed in the magnetosheath and transient increases in the H components of global ground magnetograms demonstrate that the burst appeared at a time when the magnetosphere was rapidly compressed. We attribute the inverse energy dispersion to the leakage along reconnected magnetic field lines of betatron‐accelerated energetic ions in the magnetosheath, and a burst of reconnection has an extent of about 1.5 RE using combined Super Dual Auroral Radar Network radar and EPD observations.
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spelling doaj-art-6d2e47b57f014ff3b23d0d608e0e72102025-08-20T03:10:28ZengWileyGeophysical Research Letters0094-82761944-80072016-07-0143147338734710.1002/2016GL069840Inverse energy dispersion of energetic ions observed in the magnetosheathS. H. Lee0D. G. Sibeck1K.‐J. Hwang2Y. Wang3M. V. D. Silveira4M.‐C. Fok5B. H. Mauk6I. J. Cohen7J. M. Ruohoniemi8N. Kitamura9J. L. Burch10B. L. Giles11R. B. Torbert12C. T. Russell13M. Lester14NASA Goddard Space Flight Center Greenbelt Maryland USANASA Goddard Space Flight Center Greenbelt Maryland USANASA Goddard Space Flight Center Greenbelt Maryland USAInstitute of Space Physics and Applied Technology, School of Earth and Space Sciences Peking University Beijing ChinaNASA Goddard Space Flight Center Greenbelt Maryland USANASA Goddard Space Flight Center Greenbelt Maryland USAThe Johns Hopkins University Applied Physics Laboratory Laurel Maryland USAThe Johns Hopkins University Applied Physics Laboratory Laurel Maryland USABradley Department of Electrical and Computer Engineering Virginia Polytechnic Institute and State University Blacksburg Virginia USAInstitute of Space and Astronautical Science Japan Aerospace Exploration Agency Sagamihara JapanSouthwest Research Institute San Antonio Texas USANASA Goddard Space Flight Center Greenbelt Maryland USASpace Science Center University of New Hampshire Durham New Hampshire USADepartment of Earth and Space Sciences University of California Los Angeles California USADepartment of Physics and Astronomy University of Leicester Leicester UKAbstract We present a case study of energetic ions observed by the Energetic Particle Detector (EPD) on the Magnetospheric Multiscale spacecraft in the magnetosheath just outside the subsolar magnetopause that occurred at 1000 UT on 8 December 2015. As the magnetopause receded inward, the EPD observed a burst of energetic (∼50–1000 keV) proton, helium, and oxygen ions that exhibited an inverse dispersion, with the lowest energy ions appearing first. The prolonged interval of fast antisunward flow observed in the magnetosheath and transient increases in the H components of global ground magnetograms demonstrate that the burst appeared at a time when the magnetosphere was rapidly compressed. We attribute the inverse energy dispersion to the leakage along reconnected magnetic field lines of betatron‐accelerated energetic ions in the magnetosheath, and a burst of reconnection has an extent of about 1.5 RE using combined Super Dual Auroral Radar Network radar and EPD observations.https://doi.org/10.1002/2016GL069840particle escapeenergetic ionsmagnetosheathmagnetic reconnectionsolar wind‐magnetosphere interaction
spellingShingle S. H. Lee
D. G. Sibeck
K.‐J. Hwang
Y. Wang
M. V. D. Silveira
M.‐C. Fok
B. H. Mauk
I. J. Cohen
J. M. Ruohoniemi
N. Kitamura
J. L. Burch
B. L. Giles
R. B. Torbert
C. T. Russell
M. Lester
Inverse energy dispersion of energetic ions observed in the magnetosheath
Geophysical Research Letters
particle escape
energetic ions
magnetosheath
magnetic reconnection
solar wind‐magnetosphere interaction
title Inverse energy dispersion of energetic ions observed in the magnetosheath
title_full Inverse energy dispersion of energetic ions observed in the magnetosheath
title_fullStr Inverse energy dispersion of energetic ions observed in the magnetosheath
title_full_unstemmed Inverse energy dispersion of energetic ions observed in the magnetosheath
title_short Inverse energy dispersion of energetic ions observed in the magnetosheath
title_sort inverse energy dispersion of energetic ions observed in the magnetosheath
topic particle escape
energetic ions
magnetosheath
magnetic reconnection
solar wind‐magnetosphere interaction
url https://doi.org/10.1002/2016GL069840
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