Reference : The variation of different components of Jupiter's auroral emission
Scientific congresses and symposiums : Unpublished conference
Physical, chemical, mathematical & earth Sciences : Space science, astronomy & astrophysics
The variation of different components of Jupiter's auroral emission
Nichols, J. mailto [University of Leicester, University Road, Leicester, LE1 7RH, United Kingdom ;]
Clarke, J. mailto [Boston University, 725 Commonwealth Avenue, Boston, MA 02215, United States ;]
Gérard, Jean-Claude mailto [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Labo de physique atmosphérique et planétaire (LPAP) >]
Grodent, Denis mailto [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Labo de physique atmosphérique et planétaire (LPAP) >]
Hansen, K. mailto [University of Michigan, Ann Arbor, Ann Arbor, MI 48109, ;]
American Geophysical Union, Fall Meeting 2008
15 - 19 December, 2008
San Francisco
[en] 2704 Auroral phenomena (2407) ; 2756 Planetary magnetospheres (5443 ; 5737 ; 6033) ; 5706 Aurorae ; 5737 Magnetospheres (2756)
[en] In this paper we use the extensive HST data set obtained over two month-long campaigns in 2007 to determine the long term variability of the different components of Jupiter's auroras. We define three regions on the planet's disc, i.e. the main oval, the low latitude, and high latitude auroras, and extract the UV auroral power emitted therefrom. The high latitude region was also further divided into the polar inner and polar outer regions. We discuss the temporal variation of these parameters with reference to the auroral morphology and estimated solar wind conditions projected to Jupiter's orbit from data obtained at Earth orbit. We show that the auroral morphology was very different between the first and second campaigns. In the first campaign the emitted power originated mainly from the main oval and the high latitude regions, which roughly correlated, and exhibited enhancements that are suggested to be associated with compression regions. In the second campaign the high latitude and main oval auroras were generally dimmer overall and less variable, while the low latitude region was populated with bright, patchy emission. We show that a particular auroral morphology is probably associated specifically with compression regions, i.e. over longitudes greater than approx. 180 degrees the main oval is bright and located approx. 1 degree poleward of its previous location, while over smaller longitudes the main oval is not bright or well defined. Instead there is bright emission originating from the contiguous poleward region in the afternoon/dusk sector where bright, sometimes multiple arcs form. It remains unclear, however, whether this state is a response to the initial shock or some other event within the rapidly-varying compression regions. We also show that the dawn storm events, typically associated with intense dawn side main oval auroras also result in the brightening of the high latitude auroras, even to the very highest latitude components, which presumably map to a very different region of the magnetosphere. However, apart from the dawn storms and bright poleward arcs in the afternoon/dusk sector, the power emitted from the poleward auroras is generally uncorrelated with that of the main oval.
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