Complex sentence: The region between 3 and 7--8 R s--inner magnetosphere contains the densest plasma in the saturnian system, which originates from the inner icy moons and particularly from Enceladus.
Split into simpler sentences: The region between 3 and 7--8 R s, the inner magnetosphere, contains the densest plasma in the Saturnian system. The plasma originates from the inner icy moons and particularly from Enceladus.