ORBi: Kurth William - Comparisons of Saturn Kilometric Radiation and Saturn's UV Aurora

Reference : Comparisons of Saturn Kilometric Radiation and Saturn's UV Aurora


	Document type :	Scientific congresses and symposiums : Unpublished conference
	Discipline(s) :	Physical, chemical, mathematical & earth Sciences : Space science, astronomy & astrophysics
	To cite this reference:	http://hdl.handle.net/2268/34036

Title :	Comparisons of Saturn Kilometric Radiation and Saturn's UV Aurora
Language :	English
Author, co-author :	Kurth, William [University of Iowa > Department of Physics and Astronomy >]
	Gurnett, D. A. [University of Iowa > Department of Physics and Astronomy >]
	Clarke, J. T. [Boston University > Department of Astronomy >]
	Desch, M. [NASA/Goddard Space Flight Center >]
	Kaiser, M. [NASA/Goddard Space Flight Center >]
	Zarka, P. [Observatoire de Paris >]
	Cecconi, B. [Observatoire de Paris >]
	Lecacheux, A. [Observatoire de Paris >]
	Galopeau, P. [CETP/UVSQ >]
	Gérard, Jean-Claude [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Labo de physique atmosphérique et planétaire (LPAP) >]
	Grodent, Denis [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Labo de physique atmosphérique et planétaire (LPAP) >]
	Dougherty, M. [Imperial College > Blackett Laboratory>]
	Crary, F. [Southwest Research Institute >]
Publication date :	17-May-2004
Page number :	1
On invitation :	No
Audience :	International
Event name :	American Geophysical Union Spring Meeting 2004
Event date :	17-21 May, 2004
Event organizer :	American Geophysical Union
Event place (city) :	Montreal
Event country :	Canada
Keywords :	[en] 2704 Auroral phenomena (2407) ; 2784 Solar wind/magnetosphere interactions ; 5737 Magnetospheres (2756) ; 6275 Saturn ; 6954 Radio astronomy
Abstract :	[en] During the period 8 to 30 January 2004, a campaign to study the correlation between the solar wind and the response of Saturn's aurora was carried out using Cassini and the Hubble Space Telescope. In particular, fields and particles instruments on Cassini were used to monitor the solar wind near Saturn and Saturn kilometric radio emissions nearly continuously. STIS images from Hubble were obtained approximately every other day to record Saturn's UV auroral morphology and intensity. In this paper we focus particularly on the relationship between the Saturn kilometric emissions and the auroral brightness and morphology. The radio emissions are generally believed to be generated by the cyclotron maser instability on auroral field lines similar to the situation for auroral kilometric radiation at Earth. A number of studies have shown a direct relationship between the radio emissions and discrete auroral arcs at Earth. Hence, one expects a relationship between the radio emissions and the aurora at Saturn. During the campaign, two corotating interaction regions (CIRs) swept past Cassini and Saturn (which were of order 0.5 AU apart at the time). Accompanying the CIRs were high solar wind densities. As expected from Voyager studies, the higher solar wind density resulted in generally more intense radio emissions. The UV images show that Saturn's UV aurora brighten considerably in response to the CIRs, as well. Furthermore, the brightest aurora usually appear in the local morning, consistent with the Voyager-determined SKR source region on field lines connecting to the magnetopause and the Kelvin-Helmholtz hypothesis for the origin of accelerated electrons. A more detailed examination of the auroral phenomena show much more complex variations, however. The radio emission frequency extent and peak frequency vary remarkably from one Saturn rotation to the next. Similarly, the auroral morphology changes dramatically. For example, it appears the evolution of the auroral oval to higher latitudes (higher L-shells) is correlated with a shift in the frequency of peak radio emissions to lower frequencies. This can be explained through an analysis of the cyclotron maser beaming geometry. We examine this and other aspects of the correlations between the radio emissions and the aurora.
Target :	Researchers ; Professionals
Permalink :	http://hdl.handle.net/2268/34036
Other URL :	http://adsabs.harvard.edu/abs/2004AGUSMSM12A..05K

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