On the Linear Damping Relation for Density Waves in Saturn's Rings

We revisit the equation for viscous damping of density waves derived from linearized theory. We show that in addition to the coefficient of shear viscosity itself the dependence of this coefficient on the rings surface mass density appears, as well as the coefficient of bulk viscosity. This was noted more than thirty years ago by Goldreich and Tremaine [1978]. These terms are usually neglected when fitting the viscosity from observations, but the physical effects associated with them might well be quantitatively ...