Скачать или смотреть Prof. Michele Dougherty | Magnetic Perspective on the Interior of Saturn

Speaker(s): Professor Michele Dougherty (Imperial College London)
Date: 13 September 2022 – 11:15 to 12:00
Venue: INI Seminar Room 1
Session Title: Magnetic Perspective on the Interior of Saturn (Invited speaker)
Event: [DY2W01] Dynamos in planets and stars - similarities and differences

Co-Author, Hao Cao

Magnetic fields are windows into planetary interiors and Saturn’s internal magnetic field following the Cassini Grand Finale orbital phase continues to surprise us. The unique geometry of these orbits provided an opportunity to measure the internal magnetic field at closer distances to the planet than ever encountered before. The surprising close alignment of Saturn’s magnetic axis with its spin axis (known about since the early Pioneer 11 observations) has been confirmed, however external effects, observed even around closest approach are masking some of the magnetic field signals from the interior. The varying northern and southern magnetospheric planetary period oscillations and field aligned currents at both high and low latitudes are contributing to the magnetic signals observed. We show the directly determined northward offset of Saturn’s magnetic equator and its “longitudinal” variations, small-scale yet highly consistent magnetic structures along the latitudinal direction detected along every Grand Finale orbit. Observational constraints on the electromagnetic induction response from the semi-conducting region and time variation of Saturn’s internal magnetic field will also be presented. We will discuss how these latest measurements provide a new perspective on answering some key questions concerning Saturn’s interior: level of differential rotation, the existence and extent of stable stratification, and the size and nature of the central core.