  The interaction between the solar wind and a magnetosphere is fundamental to
the dynamics of a planetary system. Here, we address fundamental questions on
the large-scale magnetosheath flow around Saturn using a 3D magnetohydrodynamic
(MHD) simulation. We find Saturn's polar-flattened magnetosphere to channel
~20% more flow over the poles than around the flanks at the terminator.
Further, we decompose the MHD forces responsible for accelerating the
magnetosheath plasma to find the plasma pressure gradient as the dominant
driver. This is by virtue of a high-beta magnetosheath, and in turn, the
high-MA bow shock. Together with long-term magnetosheath data by the Cassini
spacecraft, we present evidence of how nonaxisymmetry substantially alters the
conditions further downstream at the magnetopause, crucial for understanding
solar wind-magnetosphere interactions such as reconnection and shear
flow-driven instabilities. We anticipate our results to provide a more accurate
insight into the global conditions upstream of Saturn and the outer planets.
