Electric field variability and classifications of Titan's magnetoplasma environment

TL;DR

This paper investigates the variability of Titan's magnetoplasma environment, focusing on how quasi-periodic modulations affect the convection electric field and emphasizing the need for careful categorization in studies of Titan's magnetospheric interactions.

Contribution

It provides a quantitative analysis of electric field perturbations caused by plasma modulations, highlighting the complexity of Titan's upstream magnetospheric environment.

Findings

Electric field can deviate significantly from the nominal orientation.

Quasi-periodic modulations impact the convection electric field.

Upstream categorization schemes require careful application.

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.