Swarm Observations of Dawn/Dusk Asymmetries Between Pedersen Conductance in Upward and Downward Field‐Aligned Current Regions

L. Olifer; C. Feltman; R. Ghaffari; S. Henderson; D. Huyghebaert; J. Burchill; A. N. Jaynes; D. Knudsen; K. McWilliams; J. I. Moen; A. Spicher; J. Wu

doi:10.1029/2020EA001167

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Swarm Observations of Dawn/Dusk Asymmetries Between Pedersen Conductance in Upward and Downward Field‐Aligned Current Regions

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Swarm Observations of Dawn/Dusk Asymmetries Between Pedersen Conductance in Upward and Downward Field‐Aligned Current Regions

L. Olifer, C. Feltman, R. Ghaffari, S. Henderson, D. Huyghebaert, J. Burchill, A. N. Jaynes, D. Knudsen, K. McWilliams, J. I. Moen, …

Earth and space science (Hoboken, N.J.), Vol.8(7), e2020EA001167

07/2021

DOI: 10.1029/2020EA001167

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Abstract

The locations of region 1 and 2 field‐aligned current systems were determined using fluxgate magnetometer measurements from 875 dawn‐dusk passes of the Swarm A satellite. Within each field‐aligned current region, the ionospheric Pedersen conductance was derived from the newly corrected Swarm electric and magnetic field measurements. The Pedersen conductances are generally consistent with photoionization models. However, we show that the in situ method of determining Pedersen conductance allows for a more complete description of magnetosphere‐ionosphere coupling and should be used in future studies when possible. We show that, overall, the Pedersen conductance is larger in the upward current region than in the downward region by ∼0.6 S on the dawn side of the Earth. Meanwhile, the dusk side Pedersen conductance is equivalent in both current regions. We attribute this asymmetry to dawn side energetic electron precipitation, commonly associated with substorm electron injections from the magnetotail. Key Points In situ Pedersen conductance in field‐aligned current (FAC) regions are obtained from the Swarm measurements of the magnetic field and plasma flow velocity Pedersen conductance is larger in the upward than downward FAC regions on the dawn side, the dusk side values are similar in both regions Asymmetry between dawn and dusk current regions is attributed to intense electron precipitation commonly associated with substorm injections

Field Aligned Currents

particle precipitation

Pedersen conductance

Swarm

Details

Title: Subtitle: Swarm Observations of Dawn/Dusk Asymmetries Between Pedersen Conductance in Upward and Downward Field‐Aligned Current Regions
Creators: L. Olifer - University of Alberta
C. Feltman - University of Iowa
R. Ghaffari - University of Calgary
S. Henderson - University of Iowa
D. Huyghebaert - University of Saskatchewan
J. Burchill - University of Calgary
A. N. Jaynes - University of Iowa
D. Knudsen - University of Calgary
K. McWilliams - University of Saskatchewan
J. I. Moen - University of Oslo
A. Spicher - University of Oslo
J. Wu - University of Calgary
Resource Type: Journal article
Publication Details: Earth and space science (Hoboken, N.J.), Vol.8(7), e2020EA001167
DOI: 10.1029/2020EA001167
ISSN: 2333-5084
eISSN: 2333-5084
Number of pages: 11
Grant note: Research council of Norway (275653) Norwegian Agency for International Cooperation and Quality Enhancement in Higher Education Gouvernement du Canada, Canadian Space Agency (CSA)
Language: English
Date published: 07/2021
Academic Unit: Physics and Astronomy; University College Courses
Record Identifier: 9984428800502771

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