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Stability within Jupiter’s polar auroral ‘Swirl Region’ over moderate timescales

journal contribution
posted on 13.01.2016, 10:25 by Thomas Stephen Stallard, J. T. Clarke, H. Melin, S. Miller, Jon D. Nichols, J. O'Donoghue, Rosie E. Johnson, J. Connerney, T. Satoh, Michael Perry
Jupiter’s Swirl region, poleward of the main auroral emission, has been characterised in previous observations as having highly variable auroral emission, changing dramatically across the region on a two-minute timescale, the typical integration time for UV images. This variability has made comparisons with H3+ emission difficult. Here, we show that the Swirl region in H3+ images is characterised by relatively stable emission, often with an arc of emission on the boundary between the Swirl and Dark regions. Coadding multiple UV images taken over the approximate lifetime of the H3+ molecule in the ionosphere, show similar structures to those observed in the H3+ images. Our analysis shows that UV auroral morphology within Jupiter’s Swirl region is only highly variable on short timescales of ∼100 s, an intrinsic property of the particle precipitation process, but this variability drops away on timescales of 5–15 min. On moderate timescales between 10 and 100 min, the Swirl region is stable, evolving through as yet unknown underlying magnetospheric interactions. This shows that observing the UV aurora over timescales 5–15 min resolves clear auroral structures that will help us understand the magnetospheric origin of these features, and that calculating the variability over different timescales, especially >15 min, provides a new and important new tool in our understanding of Jupiter’s polar aurora.

History

Citation

Icarus, 2016, 268, pp. 145-155

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy

Version

AM (Accepted Manuscript)

Published in

Icarus

Publisher

Elsevier for Academic Press Inc.

issn

0019-1035

Acceptance date

22/12/2015

Available date

05/01/2018

Publisher version

http://www.sciencedirect.com/science/article/pii/S0019103515006107

Notes

The file associated with this record is under a 24-month embargo from publication in accordance with the publisher's self-archiving policy. The full text may be available through the publisher links provided above.

Language

en

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