| Affiliation: | 1Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT; 2ESTEC/ESA, RSSD-ST, Keplerlaan 1, 2201 AZ Noordwijk, the Netherlands; 3Department of Earth and Planetary Science, Washington University, Box 1169, 1 Brookings Drive, St Louis, MO 63130, USA; 4Department of Physics and Astronomy, University of Wales, Cardiff, 5 The Parade, Cardiff CF24 3YB; 5Space Science Department, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX; 6Astronomical Institute, University of Amsterdam, Kruislaan 403, 1098 SJ Amsterdam, the Netherlands |
