Saturn's Magnetic Field at Unprecedented Detail Achieved by Cassini's Close Encounters

TL;DR

The Cassini mission's close encounters with Saturn provided detailed insights into its magnetic field, revealing complex structures and raising new questions about its interior and magnetosphere.

Contribution

This study presents unprecedented high-resolution measurements of Saturn's magnetic field from Cassini's close orbits, uncovering new features and dynamics.

Findings

Detection of persistent low-latitude field-aligned currents

Observation of Alfvén waves near the D-ring

Extreme axisymmetry of Saturn's magnetic field

Abstract

The last 22.5 orbits of the Cassini mission brought the spacecraft to less than 3000 km from Saturn's 1-bar surface. These close encounters offered an unprecedented view of Saturn's magnetic field, including contributions from the internal dynamo, the ionosphere, and the magnetosphere. In this chapter, we highlight the new picture of Saturn's magnetic field from the Cassini mission including the persistent yet time-varying low-latitude field-aligned currents, Alfv\'en waves planet-ward of the D-ring, extreme axisymmetry, and high-degree magnetic moments. We then discuss the implications and new questions raised for Saturn's innermost magnetosphere, equatorial ionosphere, and interior. We conclude this chapter with an outlook for the future exploration of Saturn and other giant planets.