Supervisor : Prof Stan Cowley (swhc1@ion.le.ac.uk)

Details of Project

Images of Saturn in ultraviolet light obtained by the Hubble Space Telescope under southern summer conditions, showing the southern aurora surrounding the south magnetic pole under usual quiet conditions (left), and when the planet’s magnetosphere is strongly compressed by high-density solar wind plasma flowing out from the Sun (right).

The Cassini spacecraft has been in orbit around Saturn since 2004, yielding a large volume of data on the properties of Saturn’s outer plasma environment that is planned to continue via an extended mission phase until 2017.  Work to date has revealed a complex magnetosphere that is strongly influenced by the flow of the solar wind on the outside, and by coupling to the rotation of the upper atmosphere of the planet on the inside. 

A number of outstanding questions have been raised by these studies that need to be addressed by future research, which could thus form the basis of PhD projects. 

• What is the origin of the pervasive oscillations in the magnetic field, plasma populations, and radio emissions that are found to occur near the rotation period of the planet? 
• How do these evolve with Saturn’s seasons? 
• What is the nature of the electric current systems that couple the magnetosphere and planetary atmosphere? 
• How are these related to Saturn’s auroral emissions? 
• How do they depend on the state of the solar wind? 

PhD research projects may involve not only data analysis, but also related theory and modelling, depending on project and interests.

Sources of Data

The principal resource for these projects is data from the Cassini spacecraft, available through our co-investigator role in the Cassini magnetic field investigation, and through established collaborative contacts with other instrument teams that are responsible for particle and radio wave measurements.  Auroral data are derived from ground-based telescopes, the Hubble Space Telescope, and from Cassini itself, and are also available through established collaborative contacts. 

Background Reading

Examples of research papers that have been produced in this area by recent Leicester PhD students working with Professor Cowley

Kay Clarke et al., Magnetospheric period oscillations of Saturn’s bow shock, J. Geophys. Res., 115, A05202, doi: 10.1029/2009JA015164, 2010 

Stephanie Kellett et al., Saturn’s ring current: Local time dependence and temporal variability, J. Geophys. Res., 116, A05220, doi:10.1029/2010JA016216, 2011

David Andrews et al., Planetary period oscillations in Saturn’s magnetosphere: Evidence in magnetic field phase data for rotational modulation of Saturn kilometric radiation emissions, J. Geophys. Res., 116, A09206, doi: 10.1029/2011JA016636, 2011