Department of Physics and Astronomy, University of Leicester, Leicester, UK

Department of Physics and Astronomy, University of Leicester, Leicester, UK

Department of Physics and Astronomy, University of Leicester, Leicester, UK

Mullard Space Sciences Laboratory, University College London, Surrey, UK

Department of Physics and Astronomy, University of Leicester, Leicester, UK

Heliophysics Division, NASA GSFC, Greenbelt, MD, USA

Department of Physics and Astronomy, University of Leicester, Leicester, UK

British Antarctic Survey, Natural Environment Research Council, High Cross, Cambridge, UK

Laboratory of Planetary and Atmospheric Physics, University of Liege, Liege, Belgium