Parameterization of Observed Saturn Z-Mode Wave Power for r < 4Rs

Recent work has shown that z-mode/electron wave-particle interactions can lead to electron acceleration in the Saturn magnetosphere. These electrons may then form a partial source of Saturn's radiation belt which peaks in the range ~2R_s < r ~4R_s. The wave acceleration process depends on the local plasma density and on the distribution of z-mode wave power in frequency and spatial coordinates. In this study we bin the z-mode wave power observed by the Cassini radio and plasma wave science (RPWS) investigation in the region r < 4R_s at Saturn, where the condition f_p/f_c < 1 can be met (f_p = plasma freq., f_c = cyclotron freq.). The spatial bins include L-shell (based on a magnetic field model), latitude, and local time. Within each spatial bin we calculate the mean power-versus-frequency profile relative to f_c, which can then be analytically fit. One goal of the study is to provide a database for use in quasilinear models requiring the calculation of pitch angle and momentum diffusion coefficients. In this report we present our initial findings.