Institution: | (1) Space Science Dept., Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX, U.K;(2) Institute of Theoretical Astrophysics, University of Oslo, Oslo, Norway;(3) Department of Applied Mathematics and Theoretical Physics, Silver Street, Cambridge, CB3 9EW, U.K;(4) Nasa Goddard Space Flight Center, Greenbelt, MD, 20771, U.S.A |