Periodicity in Saturn's magnetosphere: Plasma cam

Plasma ion data from the Cassini Plasma Spectrometer (CAPS) are examined for all orbits from October 25, 2004 through Dec. 26, 2007. To eliminate effects of incomplete angular coverage, data are only used from the CAPS anode that is closest to viewing into the corotational flow and within 20 degrees of that flow. The data are plotted in the SKR-based SLS3 longitude system. The result is a cam-shaped distribution in radial distance and SLS3 that has an outer lobe extending beyond 20 R(S) at SLS3 longitudes in the range similar to 270 degrees-50 degrees. The western edge of this outer lobe maps to the inner extent of a previously observed spiral pattern of periodic ion enhancements, which had the magnetic signature of plasmoids at distances >35 Rs. The plasma cam and the plasmoid spiral emanating from it are responsible for plasma periodicities observed at radial distances beyond similar to 15 Rs in Saturn's magnetosphere. Citation: Burch, J. L., A. D. DeJong, J. Goldstein, and D. T. Young (2009), Periodicity in Saturn's magnetosphere: Plasma cam, Geophys. Res. Lett., 36, L14203, doi: 10.1029/2009GL039043.