1Mullard Space Science Laboratory, University College London, Dorking, RH5 6NT, UK
2The Centre for Planetary Sciences at UCL/Birkbeck, Gower Street, London, WC1E 6BT, UK
3Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT, UK
Received: 08 Mar 2011 – Revised: 12 May 2011 – Accepted: 22 May 2011 – Published: 19 Jul 2011
Abstract. The atmosphere of Saturn's largest moon Titan is driven by photochemistry, charged particle precipitation from Saturn's upstream magnetosphere, and presumably by the diffusion of the magnetospheric field into the outer ionosphere, amongst other processes. Ion pickup, controlled by the upstream convection electric field, plays a role in the loss of this atmosphere. The interaction of Titan with Saturn's magnetosphere results in the formation of a flow-induced magnetosphere. The upstream magnetoplasma environment of Titan is a complex and highly variable system and significant quasi-periodic modulations of the plasma in this region of Saturn's magnetosphere have been reported. In this paper we quantitatively investigate the effect of these quasi-periodic modulations on the convection electric field at Titan. We show that the electric field can be significantly perturbed away from the nominal radial orientation inferred from Voyager 1 observations, and demonstrate that upstream categorisation schemes must be used with care when undertaking quantitative studies of Titan's magnetospheric interaction, particularly where assumptions regarding the orientation of the convection electric field are made.
Arridge, C. S., Achilleos, N., and Guio, P.: Electric field variability and classifications of Titan's magnetoplasma environment, Ann. Geophys., 29, 1253-1258, doi:10.5194/angeo-29-1253-2011, 2011.