Margaret G. Kivelson

As a space physicist, I combine theory and data interpretation to study the magnetospheres of Earth and Jupiter thus to learn about the large-scale dynamical processes that occur in magnetized plasmas under a broad range of physical conditions. My collaborators and I have described theoretically the interactions between energetic charged particles and magnetohydrodynamic (MHD) waves in Earth's magneto-sphere. We have also described the compressional normal modes of the magnetospheric cavity or waveguide and related them to the low frequency MHD spectrum of the magnetosphere. In both of these areas, we have linked analysis to spacecraft observations. I lead the Galileo magnetometer team that recently co-discovered the intrinsic magnetic field of Jupiter's moon, Ganymede, and characterized its properties. The team demonstrated that Callisto and Europa respond inductively to the time-varying magnetic fields imposed on them by Jupiter's rotation and suggested that the inferred electrical currents flow in subsurface oceans. With data from more than two years in Jovian orbit, we are beginning to establish features of plasma transport unique to Jupiter's giant magnetosphere.