Discovery of Alfvén Waves Planetward of Saturn's Rings

Between April and September 2017 in the final stages of Cassini Saturn Orbiter mission spacecraft executed 22 orbits passing planetward innermost ring, D-ring. During all periapsis passes oscillations were detected azimuthal magnetic field components on typical time scales a few minutes. We argue that these time-varying signals are also primarily plasma frame. Furthermore, we show nearly exhibit spatial feature, namely node near effective line equator. propose associated with Alfvén waves excited local resonances, most likely driven from global sources.