Ray-Tracing Analysis for the Propagation of Saturn Narrowband Emission Within the Saturnian Magnetosphere

Abstract

This study investigates the propagation characteristics of Saturn's Narrowband (NB) emissions using a 3D ray-tracing code incorporating Saturn's magnetic field and electron density parameters. The potential source regions and propagation zones of the L-O mode, Z mode and whistler mode NB emissions are distinguished. The L-O mode NB emissions, generated along local electron plasma frequency surfaces through mode conversion, exhibit straight-line propagation but undergo reflections between the ionosphere, the plasma torus, and the magnetosheath. The slot region, characterized by a lower electron density distributed around the plasma torus boundary, significantly influences emission propagation, potentially leading to trapping and depolarization. The 5 kHz Z mode NB emissions propagate and fill the trapping region delineated by lower cut-off and upper hybrid resonance frequencies. In contrast, the 20 kHz Z mode NB emissions are primarily confined near source regions at the north and south edges of the plasma torus, with the possibility of escaping under variable plasma conditions.