Origin of Neutral Gas with Peculiar Velocity in the Saturn E-ring

The materials of Saturn E-ring are known to have originated from the satellite Enceladus. Once leaving the satellite, either by surface sputtering, outgassing plumes, or other mechanisms, the ejected material is subject to several forces in synergy, among which gravity, electromagnetic forces, and radiation forces. In consequence, unlike Enceladus, which is massive enough to follow a Keplerian orbit, all kinds of trajectories are manifested by small particles. Particles with a large mass-to-charge ratio barely feel the sweeping magnetic field that is co-rotating with Saturn. On the other hand, particles with small mass-to-charge ratio have small gyro-radius, and thus are bound to the magnetic field lines. Through Hamiltonian analysis, we discovered that particles with intermediate mass-to-charge ratio may form a distinct population of ring particles. This population can exhibit some peculiar velocity signatures that are verifiable through observations.