Modeling the Strength and Radial Variation of the Magnetic Field Generated by Jupiter’s Current Sheet

Abstract:

Galileo and Juno spacecraft have together surveyed Jupiter’s magnetospheric current sheet over a vast set of local times, radial distances and latitudes. The Jovian current sheet which is the main repository of Jupiter’s magnetospheric plasma, stretches and shapes the magnetic field of Jupiter and its magnetosphere. A good quantitative model of its contribution to the magnetospheric field is highly desired.

We are building a new global model of Jupiter’s magnetospheric field informed by data from all of the spacecraft that have visited Jupiter so far. In this presentation, we discuss building a model of Jupiter’s current sheet field by using the analytical models of disk-shaped current sheets advanced by Tsyganenko and Peredo [JGR, 1994]. The technique involves constructing several self-similar modes of current sheet and inferring the strength of each mode using a least squares inversion technique. We find that a total of 3 modes which peak at L =4, L=15 and L=100 and fall off steeply with distance and a symmetric ring current mode centered at 8 R_J are able to describe the field of the current sheet quite accurately.

We will provide a comparison of the external magnetospheric field of Jupiter with that obtained from our current sheet model in this presentation. We show that overall the model fits the observations quite well but does differs from the observations in local time because the model so far lacks sources of local time asymmetry such as the magnetopause field and the differences in the thickness of the current sheet over local time. We intend to incorporate these additional sources in a future global model.