New insights on Titan's plasma-driven Schumann resonance inferred from Huygens and Cassini data

摘要: Abstract After a preliminary analysis of the low-frequency data collected with electric antenna Permittivity, Wave and Altimetry (PWA) experiment onboard Huygens Probe that landed on Titan 14 January, 2005, it was anticipated in previous article [Beghin et al., 2007. A Schumann-like resonance driven by Saturn's magnetosphere possibly revealed Probe. Icarus, 191, 251–266] Extremely Low-Frequency (ELF) signal at around 36 Hz observed throughout descent, might have been generated upper ionosphere Titan, plasma instability mechanism associated co-rotating Kronian flow. The involved process proposed as most likely source Schumann moon's atmospheric cavity, second eigenmode which is actually found models to occur 36 Hz. In this paper, we present thorough based upon attitude deduced from Descent Imager Spectral Radiometer (DISR), relevant measurements obtained Radio Plasma Science (RPWS) magnetometer (MAG) Cassini orbiter during flybys Titan. We derived several coherent characteristics confirm validity initially provide new significant insights about such unique type solar system. Indeed, contains all polarized wave, measured field horizontal component modulated rotation, an altitude profile agreement Longitudinal Section Electric (LSE) cavity. contrast Earth's conditions where conventional Transverse Magnetic mode considered, LSE appears be only one complying observations unexpected peculiar These are essentially lack any lightning activity can ascertained observations, presence ionized layer centered 62 km discovered PWA instrumentation, existence subsurface conducting boundary mandatory for trapping ELF waves. simple theoretical model our places tentatively consequential constraints conductivity lower ionosphere. It also consistent conductive water ocean below icy crust some tens kilometers thick.