Using crossings of Saturn's magnetospheric boundaries to explore the link between upstream conditions and radio emission

Abstract

Saturn has several components to its radio emission which can change in response to varying solar wind and magnetospheric conditions. These radio components include the Saturn Kilometric Radiation (SKR), a cyclotron maser instability-generated emission which occasionally displays Low Frequency Extensions (LFEs), some of which can last for more than a planetary rotation. We utilise a list of all magnetopause and bow shock crossings by Cassini during its 13-year tour of the Saturn system to explore how measurements of the upstream and near-boundary conditions at Saturn can inform our knowledge of the solar wind driving and its links to radio emission. Solar wind intervals give a direct measure of the upstream environment to compare against. Furthermore, bow shock and magnetopause crossings can be used in concert with boundary models to infer the upstream solar wind dynamic pressure at the time of crossings. We show several case studies which elucidate the timeline of solar wind-magnetosphere-ionosphere coupling at Saturn and outline open questions and future avenues for exploration.