Open questions about Saturn´s radio emissions

The Cassini spacecraft collected lots of valuable scientific data during its 13 year-long tour (2004- 2017) around Saturn. The so-called Radio and Plasma Wave Science (RPWS) instrument mainly investigated Saturns radio emissions like Saturn Kilometric Radiation (SKR), narrowband emissions (NB), Saturn lightning, and newly identified emissions like Saturn Drifting Bursts (SDBs) and Saturn Anomalous Myriametric (SAM) radiation. Some important discoveries were made like the changing periodicity of the radio emissions. However, there are still several open questions, and the RPWS data set can be considered as a treasure chest, in which several jewels remain to be found. One of the main goals of our project is to comprehensively investigate the radio wave polarization properties of all the mentioned Saturn radio emissions. For example, SKR is usually totally circularly polarized, and it is right-handed when the source is in the northern aurora and left-handed when it comes from the South. However, SKR also shows elliptical polarization or partial polarization at very low frequencies, and these phenomena have hardly been investigated. Radio emissions from Saturn lightning were shown to have a right-handed circular component when the lightning storm was in the southern hemisphere, and some lightning radio emissions from the great lightning storm at mid-latitudes in the north were found to be left-handed polarized. Thus it could also be the case that the sense of polarization depends on the hemisphere of the source, like for SKR. However, only a small amount of data has been analyzed, and we will check the polarization of all known Saturn lightning events. Surprisingly, until today not much is known about the newly detected radio emissions of Saturn drifting bursts (SDBs), and we will look at the complete RPWS data set to evaluate their occurrence, intensity, and polarization distributions with respect to Saturn orbital parameters like distance, latitude, and local time. Our second main goal is to perform radio wave direction finding of all those emissions to better constrain their source locations, and in some cases to better understand their generation processes. The primary researchers of this joint international 3-year project are Dr. Georg Fischer from the University of Graz on the Austrian side and Dr. Ulrich Taubenschuss from the Institute of Atmospheric Physics from the Czech Academy of Sciences in Prague.