Saturn's periodic magnetic field perturbations caused by a rotating partial ring current

We demonstrate that the periodic magnetic field perturbations as observed from Cassini are caused by the plasma pressure of the energetic (>2 keV) particle distributions that are periodically injected and subsequently drift around Saturn. Plasma pressures inferred from the Cassini Plasma Spectrometer (CAPS) (<2 keV) and the Magnetospheric Imaging Instrument (MIMI) (>2 keV) are used to compute the three-dimensional pressure-driven currents and their associated magnetic field perturbations. The distribution of the hot (>2 keV) plasma pressure is derived from Energetic Neutral Atom (ENA) images obtained by the Ion Neutral Camera (INCA) and in-situ spectral measurements. The radial profile of cold (<2 keV) plasma pressure is obtained from statistical studies and is assumed to be azimuthally symmetric. Citation: Brandt, P. C., K. K. Khurana, D. G. Mitchell, N. Sergis, K. Dialynas, J. F. Carbary, E. C. Roelof, C. P. Paranicas, S. M. Krimigis, and B. H. Mauk (2010), Saturn's periodic magnetic field perturbations caused by a rotating partial ring current, Geophys. Res. Lett., 37, L22103, doi:10.1029/2010GL045285.