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Response of Jupiter's and Saturn's auroral activity to the solar wind
Crary, F.; Cecconi, B.; Lamy, L. +18 more
While the terrestrial aurorae are known to be driven primarily by the interaction of the Earth's magnetosphere with the solar wind, there is considerable evidence that auroral emissions on Jupiter and Saturn are driven primarily by internal processes, with the main energy source being the planets' rapid rotation. Prior observations have suggested …
Variation of different components of Jupiter's auroral emission
Nichols, J. D.; Clarke, J. T.; Grodent, D. +2 more
The Hubble Space Telescope (HST) data set obtained over two campaigns in 2007 is used to determine the long-term variability of the different components of Jupiter's auroras. Three regions on the planet's disc are defined: the main oval, the low-latitude auroras, and the high-latitude auroras. The UV auroral power emitted from these regions is ext…
An auroral oval at the footprint of Saturn's kilometric radio sources, colocated with the UV aurorae
Cecconi, B.; Lamy, L.; Nichols, J. D. +3 more
Similarly to other magnetized planets, Saturn displays auroral emissions generated by accelerated electrons gyrating around high-latitude magnetic field lines. They mainly divide in ultraviolet (UV) and infrared (IR) aurorae, excited by electron collisions with the upper atmosphere, and Saturn's kilometric radiation (SKR), radiated from higher alt…
The Io UV footprint: Location, inter-spot distances and tail vertical extent
Delamere, P. A.; Bonfond, B.; Clarke, J. T. +4 more
The Io footprint (IFP) consists of one or several spots observed in both jovian hemispheres and is related to the electromagnetic interaction between Io and the magnetosphere. These spots are followed by an auroral curtain, called the tail, extending more than 90° longitude in the direction of planetary rotation. We use recent Hubble Space Telesco…
Auroral footprint of Ganymede
Gérard, Jean-Claude; Clarke, John T.; Grodent, Denis +4 more
The interaction of Ganymede with Jupiter's fast rotating magnetospheric plasma gives rise to a current system producing an auroral footprint in Jupiter's ionosphere, usually referred to as the Ganymede footprint. Based on an analysis of ultraviolet images obtained with the Hubble Space Telescope, we demonstrate that the auroral footprint surface m…
Characterization of auroral current systems in Saturn's magnetosphere: High-latitude Cassini observations
Coates, A. J.; Dougherty, M. K.; Cowley, S. W. H. +3 more
We have identified seven periapsis passes during the first high-latitude phase of the Cassini mission, from mid-2006 to mid-2007, in which the spacecraft traversed at intermediate altitudes the region between open field lines at highest latitudes and the region inside the inner edge of the ring current. Varying azimuthal magnetic fields indicative…
Transient auroral features at Saturn: Signatures of energetic particle injections in the magnetosphere
Krupp, N.; Roussos, E.; Mitchell, D. G. +7 more
We report for the first time transient isolated auroral spots at Saturn's southern polar region, based on Hubble Space Telescope (HST) FUV images. The spots last several minutes and appear distinct from the rest of the auroral emissions. We study two sets of HST and Cassini observations during which Cassini instrumentation detected signatures of e…
Phase relation of oscillations near the planetary period of Saturn's auroral oval and the equatorial magnetospheric magnetic field
Nichols, J. D.; Cowley, S. W. H.; Provan, G.
Previous analyses of Hubble Space Telescope (HST) images of Saturn's southern auroras obtained during two campaigns, in January 2007 and February 2008, have revealed that the auroral oval oscillates at a period close to the planetary rotation period, with its center describing an elongated ellipse of semimajor axis ∼2° colatitude aligned along the…