Welcome to the website for the auroras of the outer planets ISSI Team

 

 

Science overview

 

Planetary magnetospheres, i.e. the cavities which contain and are controlled by planetary magnetic fields, provide natural laboratories for the study of cosmic plasmas. Although governed by the same fundamental laws, the magnetospheres of the planets are each strikingly different, providing important and mutually illuminating case studies. Auroral emissions provide an indispensable diagnostic tool for the energetic processes occurring in planetary magnetospheres, since they are produced when energetic processes in the magnetosphere accelerate charged particles along magnetic field lines into the planet’s polar ionosphere, whereupon they impact the atmospheric particles and produce light. Observations of auroral emission across the electromagnetic spectrum from radio to X-rays thus uniquely provide a global view of the dynamics of planetary magnetospheres, and at present are revolutionising our understanding of the plasma environments of Jupiter and Saturn. Both these planets have large magnetospheres, the dynamics of which are dominated by planetary rotation; this situation contrasts markedly to the Earth’s magnetosphere which is driven by the interaction with the solar wind, although it is becoming clear that the solar wind also affects the auroras greatly on the outer planets. Auroral observations are obtained by either Earth-based remote sensing platforms, e.g. the Hubble Space Telescope (HST), or spacecraft such as Cassini, which also provide invaluable supporting in situ measurements. Several unique data sets have recently been obtained which present different facets of the auroral process of the outer planets.  This International Team will bring together ultraviolet, infrared, X-ray, radio, and in situ particles and fields observations along with world-leading expertise in order to address the following topics:  How are the auroral emissions of different wavelengths related? How are the auroral observations related to in situ measurements? What affects the morphology of the auroral emission?  Such multi-instrument studies are crucial if we are to test the models which try and explain the dynamics of the outer planets magnetospheres, and to reach a global understanding of their manifestations.  The results will have significant bearing on the wider planetary and astrophysical community.

 

 

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