By constructing an empirical model of the spectral and wave normal angle distribution of 5 kHz and 20 kHz Saturnian Z-mode waves based on Cassini observations, we investigate the resonant interactions between Z-mode waves and radiation belt electrons at Saturn. The results of quasi-linear bounce-averaged diffusion coefficients show that Saturnian Z-mode waves can efficiently scatter radiation belt electrons (with energies up to several MeV), with the resonant pitch angle coverage becoming narrower as L-shell increases. Compared with 20 kHz waves, 5 kHz wave induced scattering occurs at higher electron energies with stronger scattering efficiency. Fokker-Planck simulations show that Z-mode waves can result in the loss of lower energy electrons and the acceleration of higher energy electrons at intermediate pitch angles, contributing to the formation of electron butterfly pitch angle distribution. Our results improve the current understanding of the role of Z-mode waves in the dynamics of Saturn's radiation belt.
 

Saturn radiation belt,Z-mode waves,Wave-particle interactions