The Cushion Region and Dayside Magnetodisc Structure at Saturn
- Ned Russell Staniland,
- Michele K. Dougherty,
- Adam Masters,
- Nicholas Achilleos
Abstract
A sustained dipolar magnetic field between the current sheet outer edge
and the magnetopause, known as a cushion region, has yet to be observed
at Saturn. Whilst some signatures of reconnection occurring in the
dayside magnetodisc have been identified, the presence of this
large-scale structure has not been seen. Using the complete Cassini
magnetometer data, the first evidence of a cushion region forming at
Saturn is shown. Only five potential examples of a sustained cushion are
found, revealing this phenomenon to be rare. This feature more commonly
occurs at dusk compared to dawn, where it is found at Jupiter. It is
suggested that due to greater heating and expansion of the field through
the afternoon sector the disc is more unstable in this region. We show
that magnetodisc breakdown is more likely to occur within the
magnetosphere of Jupiter compared to Saturn.