Series: Astronomy Unit Seminars
Speaker: Dr Nicholas Achilleos (UCL)
Abstract: The rapidly rotating magnetospheres of Jupiter and Saturn contain near-axisymmetric regions with 'disc-like' distributions of plasma, and radially distorted magnetic field lines. These so-called 'magnetodisc' regions can be well approximated, in terms of modelling, by systems in which a balance of forces prevails between: magnetic curvature, plasma pressure and centrifugal force. We will discuss the observable signatures of these plasmadiscs, as well as the adaptation of Caudal's disc model for Jupiter to treat the case of Saturn. One important difference between these two worlds is that Saturn's plasmadisc harbours comparable forces due to the centrifugal term and to hot plasma pressure, while the Jovian system appears to be more clearly dominated by the pressure gradients from the hot magnetospheric ion populations.