Work has included: HF propagation theory; interpretation of data from the EISCAT incoherent scatter radars and from the AMPTE, VIKING, ISEE, DMSP, Polar and Cluster satellites; theory of solar wind-magnetosphere- ionosphere coupling; and analysis of long data series. Areas of study have included non-thermal plasma, ionospheric plasma outflows, convection during substorms, signatures of pulsed magnetic reconnection, cusp precipitation; and long- term solar change and its effects. PI for the EARTHSHINE satellite proposal. Learned Societies: RS logo Fellow of the Royal Society of London (FRS) IOP logo Fellow, Institute of Physics (FInstP) IOP logo Chartered Physicist (CPhys) AGU logo Member, American Geophysical Union EGU logo Member, European Geoscience Union RAS logo Fellow, Royal Astronomical Society (FRAS)