Differences in the structure of a planetary magnetopause boundary layer

The boundary of a planetary magnetosphere is known as a magnetopause, and is the site of energy, mass, and momentum transfer. The structure of internal boundary layers adjacent to these boundaries is intimately related to the processes responsible for this transport. We use thermal electron observations made by the Cassini spacecraft to examine the structure of Saturn’s low-latitude internal boundary layer. By analyzing the relationship between the electron density and temperature during the crossings we demonstrate that the structure of the layer is variable. At some of the crossings the major changes in electron density and temperature occur in distinct regions of the layer (as for previously reported examples at Earth), whereas at others the two quantities change over a similar region. We discuss the possible explanations for this phenomenon, and what this could tell us about how the solar wind interacts with a planetary magnetosphere.