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JGR Space Physics - 2022 - Nichols - Relation of Jupiter s Dawnside Main Emission Intensity to Magnetospheric Currents.pdf (4.7 MB)

Relation of Jupiter's dawnside main emission intensity to magnetospheric currents during the Juno mission

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journal contribution
posted on 2024-02-06, 10:27 authored by Jonathan Nichols, Stanley WH Cowley

We compare Jupiter's dawn-side main auroral emission intensity observed by the Hubble Space Telescope with the simultaneous magnitude of the dawn-side magnetospheric equatorial radial current as observed by Juno during Orbits 3–7. We show that the peak auroral intensity and the square of the radial current per radian of azimuth are strongly correlated with R ≈ 0.9, and that the chance that the two phenomena are unrelated is negligible. We also fit empirical profiles of the total radial current flowing per radian of azimuth to the observed values and estimate the precipitating electron energy flux during each observation, and show this exhibits a similar correlation to the current. We find 1 mW m−2 of precipitating energy flux is associated with ∼5–11 kR of auroral emission, consistent with modeling studies. This is the first demonstration of a statistical relationship between the intensity of Jupiter's auroras and the strength of the magnetospheric currents, specifically the radial current, the j × B force of which accelerates plasma in the sense of planetary rotation. This result provides compelling evidence that the magnetosphere-ionosphere coupling current system at Jupiter plays a key role in powering the planet's dawn side main auroral emission. We further show that there is no association between the auroral intensity and the rate of change of the magnetic energy density outside the current sheet.

Funding

A Consolidated Grant Proposal for Solar System Research at the University of Leicester (2016-2019)

Science and Technology Facilities Council

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History

Author affiliation

School of Physics & Astronomy, University of Leicester

Version

  • VoR (Version of Record)

Published in

Journal of Geophysical Research

Volume

127

Issue

1

Publisher

American Geophysical Union

issn

0148-0227

Copyright date

2022

Available date

2024-02-06

Language

en

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