Imperial College London
Alternate

Professor Southwood

Faculty of Natural Sciences, Department of Physics

Senior Research Investigator
 
 
 
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Contact

 

+44 (0)20 7594 7770d.southwood CV

 
 
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Location

 

711AHuxley BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Archer:2023:10.1029/2022JA031081,
author = {Archer, M and Hartinger, MD and Rastatter, L and Southwood, D and Heyns, M and Eggington, J and Wright, A and Plaschke, F and Shi, X},
doi = {10.1029/2022JA031081},
journal = {Journal of Geophysical Research: Space Physics},
pages = {1--25},
title = {Auroral, ionospheric and ground magnetic signatures of magnetopause surface modes},
url = {http://dx.doi.org/10.1029/2022JA031081},
volume = {128},
year = {2023}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Surface waves on Earth's magnetopause have a controlling effect upon global magnetospheric dynamics. Since spacecraft provide sparse in situ observation points, remote sensing these modes using ground-based instruments in the polar regions is desirable. However, many open conceptual questions on the expected signatures remain. Therefore, we provide predictions of key qualitative features expected in auroral, ionospheric, and ground magnetic observations through both magnetohydrodynamic theory and a global coupled magnetosphere-ionosphere simulation of a magnetopause surface eigenmode. These show monochromatic oscillatory field-aligned currents (FACs), due to both the surface mode and its non-resonant Alfvén coupling, are present throughout the magnetosphere. The currents peak in amplitude at the equatorward edge of the magnetopause boundary layer, not the open-closed boundary as previously thought. They also exhibit slow poleward phase motion rather than being purely evanescent. We suggest the upward FAC perturbations may result in periodic auroral brightenings. In the ionosphere, convection vortices circulate the poleward moving FAC structures. Finally, surface mode signals are predicted in the ground magnetic field, with ionospheric Hall currents rotating perturbations by approximately (but not exactly) 90° compared to the magnetosphere. Thus typical dayside magnetopause surface modes should be strongest in the East-West ground magnetic field component. Overall, all ground-based signatures of the magnetopause surface mode are predicted to have the same frequency across L-shells, amplitudes that maximize near the magnetopause's equatorward edge, and larger latitudinal scales than for field line resonance. Implications in terms of ionospheric Joule heating and geomagnetically induced currents are discussed.
AU  - Archer,M
AU  - Hartinger,MD
AU  - Rastatter,L
AU  - Southwood,D
AU  - Heyns,M
AU  - Eggington,J
AU  - Wright,A
AU  - Plaschke,F
AU  - Shi,X
DO  - 10.1029/2022JA031081
EP  - 25
PY  - 2023///
SN  - 2169-9380
SP  - 1
TI  - Auroral, ionospheric and ground magnetic signatures of magnetopause surface modes
T2  - Journal of Geophysical Research: Space Physics
UR  - http://dx.doi.org/10.1029/2022JA031081
UR  - https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022JA031081
UR  - http://hdl.handle.net/10044/1/103003
VL  - 128
ER  -
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