Abstract

Saturn’s intrinsic magnetic field continues to offer surprises since the first in-situ measurements during the Pioneer 11 Saturn flyby. The Cassini spacecraft entered the Grand Finale phase in April 2017, during which time the spacecraft dived through the gap between Saturn’s atmosphere and the inner edge of the D-ring 22 times before descending into the deep atmosphere of Saturn on Sep. 15 th 2017. The unprecedented proximity to Saturn (reaching ~2550 +/- 1290 km above the cloud deck) and the highly inclined nature of the Grand Finale orbits provided an ideal opportunity to decode Saturn’s internal magnetic field. The fluxgate magnetometer onboard Cassini made precise in-situ vector magnetic field measurements during the Grand Finale phase. Magnetic signals from the interior of the planet and various magnetospheric currents were observed during the Grand Finale phase. Here we will report new features of Saturn’s internal magnetic field revealed by measurements from the Cassini Grand Finale phase. We will show the directly determined northward offset of Saturn’s magnetic equator and it variations. Small-scale yet highly consistent magnetic structures were detected along every Grand Finale orbits. When expressed in spectral space, intrinsic magnetic moments up to at least degree 9 are needed to describe these magnetic structures. Implications for the deep interior of Saturn will be discussed.