Fig. 1
From: Formation of electron radiation belts at Saturn by Z-mode wave acceleration
Z-mode and O-mode emission observed by the Cassini RPWS instrument. a Electric field power spectral density from RPWS on Cassini. The electron gyro frequency, fce, is marked by the solid white line. The white plus signs indicate the plasma frequency and the pink crosses mark the L mode cut-off frequency. b Apparent circular polarization20,21 as observed by the RPWS for the same time period. Prior to 10:23, apparent circular polarization <0 (blue) is left-hand polarized; after this time >0 (red) is left-hand polarized as indicated by the labels RCP and LCP in the figure
