Multipoint MMS observations of fine‐scale SAPS structure in the inner magnetosphere

Abstract We present detailed observations of dynamic, fine‐scale inner magnetosphere‐ionosphere coupling at ∼3.9 RE in the Region 2 Birkeland field‐aligned current (FAC). We find that observed electrodynamic spatial/temporal scales are primarily characteristic of magnetically mapped ionospheric stru...

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Main Authors: P. J. Erickson, H. Matsui, J. C. Foster, R. B. Torbert, R. E. Ergun, Yu. V. Khotyaintsev, P.‐A. Lindqvist, M. R. Argall, C. J. Farrugia, K. W. Paulson, R. J. Strangeway, W. Magnes
Format: Article
Language:English
Published: Wiley 2016-07-01
Series:Geophysical Research Letters
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Online Access:https://doi.org/10.1002/2016GL069174
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author P. J. Erickson
H. Matsui
J. C. Foster
R. B. Torbert
R. E. Ergun
Yu. V. Khotyaintsev
P.‐A. Lindqvist
M. R. Argall
C. J. Farrugia
K. W. Paulson
R. J. Strangeway
W. Magnes
author_facet P. J. Erickson
H. Matsui
J. C. Foster
R. B. Torbert
R. E. Ergun
Yu. V. Khotyaintsev
P.‐A. Lindqvist
M. R. Argall
C. J. Farrugia
K. W. Paulson
R. J. Strangeway
W. Magnes
author_sort P. J. Erickson
collection DOAJ
description Abstract We present detailed observations of dynamic, fine‐scale inner magnetosphere‐ionosphere coupling at ∼3.9 RE in the Region 2 Birkeland field‐aligned current (FAC). We find that observed electrodynamic spatial/temporal scales are primarily characteristic of magnetically mapped ionospheric structure. On 15 September 2015, conjugate Magnetospheric Multiscale (MMS) spacecraft and Millstone Hill radar observations show plasmasphere boundary region subauroral polarization stream (SAPS) electric fields at L = 4.0–4.2 near 21 MLT. MMS observations reveal high‐altitude ∼1 mV/m fine‐scale radial and azimuthal electric field perturbations over ≤0.15 L with high spatial coherence over ≥2–3 min and show outward motion within a broader FAC of ∼0.12 μA/m2. Our analysis shows that MMS electric field fluctuations are most likely reflective of SAPS ionospheric structure at scales of ∼22 km and with ionospheric closure of small‐scale filamentary FAC perturbations. The results highlight the ionosphere's importance in regulating fine‐scale magnetosphere‐ionosphere structure.
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series Geophysical Research Letters
spelling doaj-art-2ac5f5a6af444b1ba8d565570e1b9dc82025-08-20T03:49:41ZengWileyGeophysical Research Letters0094-82761944-80072016-07-0143147294730010.1002/2016GL069174Multipoint MMS observations of fine‐scale SAPS structure in the inner magnetosphereP. J. Erickson0H. Matsui1J. C. Foster2R. B. Torbert3R. E. Ergun4Yu. V. Khotyaintsev5P.‐A. Lindqvist6M. R. Argall7C. J. Farrugia8K. W. Paulson9R. J. Strangeway10W. Magnes11Haystack Observatory Massachusetts Institute of Technology Westford Massachusetts USASpace Science Center University of New Hampshire Durham New Hampshire USAHaystack Observatory Massachusetts Institute of Technology Westford Massachusetts USASpace Science Center University of New Hampshire Durham New Hampshire USASpace Science Center University of New Hampshire Durham New Hampshire USASpace Science Center University of New Hampshire Durham New Hampshire USASpace Science Center University of New Hampshire Durham New Hampshire USASpace Science Center University of New Hampshire Durham New Hampshire USASpace Science Center University of New Hampshire Durham New Hampshire USASpace Science Center University of New Hampshire Durham New Hampshire USAInstitute of Geophysics and Planetary Physics University of California Los Angeles California USASpace Research Institute, Austrian Academy of Sciences Graz AustriaAbstract We present detailed observations of dynamic, fine‐scale inner magnetosphere‐ionosphere coupling at ∼3.9 RE in the Region 2 Birkeland field‐aligned current (FAC). We find that observed electrodynamic spatial/temporal scales are primarily characteristic of magnetically mapped ionospheric structure. On 15 September 2015, conjugate Magnetospheric Multiscale (MMS) spacecraft and Millstone Hill radar observations show plasmasphere boundary region subauroral polarization stream (SAPS) electric fields at L = 4.0–4.2 near 21 MLT. MMS observations reveal high‐altitude ∼1 mV/m fine‐scale radial and azimuthal electric field perturbations over ≤0.15 L with high spatial coherence over ≥2–3 min and show outward motion within a broader FAC of ∼0.12 μA/m2. Our analysis shows that MMS electric field fluctuations are most likely reflective of SAPS ionospheric structure at scales of ∼22 km and with ionospheric closure of small‐scale filamentary FAC perturbations. The results highlight the ionosphere's importance in regulating fine‐scale magnetosphere‐ionosphere structure.https://doi.org/10.1002/2016GL069174sub auroral polarization streamring currentregion 2 Birkeland currentmms
spellingShingle P. J. Erickson
H. Matsui
J. C. Foster
R. B. Torbert
R. E. Ergun
Yu. V. Khotyaintsev
P.‐A. Lindqvist
M. R. Argall
C. J. Farrugia
K. W. Paulson
R. J. Strangeway
W. Magnes
Multipoint MMS observations of fine‐scale SAPS structure in the inner magnetosphere
Geophysical Research Letters
sub auroral polarization stream
ring current
region 2 Birkeland current
mms
title Multipoint MMS observations of fine‐scale SAPS structure in the inner magnetosphere
title_full Multipoint MMS observations of fine‐scale SAPS structure in the inner magnetosphere
title_fullStr Multipoint MMS observations of fine‐scale SAPS structure in the inner magnetosphere
title_full_unstemmed Multipoint MMS observations of fine‐scale SAPS structure in the inner magnetosphere
title_short Multipoint MMS observations of fine‐scale SAPS structure in the inner magnetosphere
title_sort multipoint mms observations of fine scale saps structure in the inner magnetosphere
topic sub auroral polarization stream
ring current
region 2 Birkeland current
mms
url https://doi.org/10.1002/2016GL069174
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