Saturn's mid-sized moons (satellites) have a puzzling orbital configuration
with trapping in mean-motion resonances with every other pairs (Mimas-Tethys
4:2 and Enceladus-Dione 2:1). To reproduce their current orbital configuration
on the basis of Crida & Charnoz's model of satellite formation from a
hypothetical ancient massive rings, adjacent pairs must pass 1st-order
mean-motion resonances without being trapped. The trapping could be avoided by
fast orbital migration and/or excitation of the satellite's eccentricity caused
by gravitational interactions between the satellites and the rings (the disk),
which are still unknown. In our research, we investigate the satellite orbital
evolution due to interactions with the disk through full N-body simulations. We
performed global high-resolution N-body simulations of a self-gravitating
particle disk interacting with a single satellite. We used N∼105
particles for the disk. Gravitational forces of all the particles and their
inelastic collisions are taken into account. As a result, dense
short-wavelength wake structure is created by the disk self-gravity and global
spiral arms with m∼ a few is induced by the satellite. The self-gravity
wakes regulate the orbital evolution of the satellite, which has been
considered as a disk spreading mechanism but not as a driver for the orbital
evolution. The self-gravity wake torque to the satellite is so effective that
the satellite migration is much faster than that was predicted with the spiral
arms torque. It provides a possible model to avoid the resonance capture of
adjacent satellite pairs and establish the current orbital configuration of
Saturn's mid-sized satellites.Comment: (6 pages, 4 figures, Accepted in A&A