1. Department of Physics and AstronomyUniversity of Leicester Leicester UK
2. Birkeland Centre for Space Science, Department of Physics and TechnologyUniversity of Bergen Bergen Norway
3. Physics and AstronomyUniversity of Southampton Southampton UK
4. Department of PhysicsUniversity of Lancaster Lancaster UK
5. Applied Physics LaboratoryThe Johns Hopkins University Laurel Maryland USA
6. Laboratory of Planetary and Atmospheric PhysicsUniversity of Liège Liège Belgium