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{Hunt:2020:10.1029/2019ja027683,
author = {Hunt, GJ and Bunce, EJ and Cao, H and Cowley, SWH and Dougherty, MK and Provan, G and Southwood, DJ},
doi = {10.1029/2019ja027683},
journal = {Journal of Geophysical Research: Space Physics},
title = {Saturn's auroral field-aligned currents: observations from the Northern Hemisphere dawn sector during cassini's proximal orbits},
url = {http://dx.doi.org/10.1029/2019ja027683},
volume = {125},
year = {2020}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - We examine the azimuthal magnetic field signatures associated with Saturn's northern hemisphere auroral fieldaligned currents observed in the dawn sector during Cassini's Proximal orbits (April 2017 and September 2017). We compare these currents with observations of the auroral currents from near noon taken during the Fring orbits prior to the Proximal orbits. First, we show that the position of the main auroral upward current is displaced poleward between the two local times (LT). This is consistent with the statistical position of the ultraviolet auroral oval for the same time interval. Second, we show the overall average ionospheric meridional current profile differs significantly on the equatorward boundary of the upward current with a sweptforward configuration with respect to planetary rotation present at dawn. We separate the planetary period oscillation (PPO) currents from the PPOindependent currents and show their positional relationship is maintained as the latitude of the current shifts in LT implying an intrinsic link between the two systems. Focusing on the individual upward current sheets passbypass we find that the main upward current at dawn is stronger compared to nearnoon. This results in the current density been ~1.4 times higher in the dawn sector. We determine a proxy for the precipitating electron power and show that the dawn PPOindependent upward current electron power ~1.9 times higher than at noon. These new observations of the dawn auroral region from the Proximal orbits may show evidence of an additional upward current at dawn likely associated with strong flows in the outer magnetosphere.
AU  - Hunt,GJ
AU  - Bunce,EJ
AU  - Cao,H
AU  - Cowley,SWH
AU  - Dougherty,MK
AU  - Provan,G
AU  - Southwood,DJ
DO  - 10.1029/2019ja027683
PY  - 2020///
SN  - 2169-9380
TI  - Saturn's auroral field-aligned currents: observations from the Northern Hemisphere dawn sector during cassini's proximal orbits
T2  - Journal of Geophysical Research: Space Physics
UR  - http://dx.doi.org/10.1029/2019ja027683
UR  - https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019JA027683
UR  - http://hdl.handle.net/10044/1/78021
VL  - 125
ER  -
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