1. Department of Physics and AstronomyUniversity College London London UK
2. Centre for Planetary SciencesUCL/Birkbeck London UK
3. Office for Space Research and TechnologyAcademy of Athens Athens Greece
4. Institute of Astronomy, Astrophysics, Space Applications, and Remote SensingNational Observatory of Athens Athens Greece
5. Department of PhysicsLancaster University Lancaster UK
6. Space and Atmospheric Physics Group, Blackett LaboratoryImperial College London London UK