摘要：In this paper, we study the effect of interparticle cohesion in numerical simulations of Saturn’s main rings.Theoretical studies propose that the irregular structure in Saturn’s rings may arise from alternating “solid” and“liquid” ring material. These studies suggest that for sufficiently high interparticle cohesion, shear-free ringsaround Saturn may form. We use a highly optimized N-body code that models particle self-gravity, soft-spherecollisions, and interparticle cohesion to simulate a patch of Saturn’s rings with periodic boundaries. We presentresults for nine different cohesion values ranging from 5.0×10 −2 to 7.0 Pa, dynamical optical depths of 0.8, 1.4,and 1.8, particle material densities of 0.5 and 1gcm −3 , and restitution coefficients of 0.8 and 0.55. Our simulationsshow a transition of ring particles forming self-gravity wakes to forming structureless uniform distributions ofsmaller and faster-moving clumps as cohesion increases. The transition from wakes to structureless form occurs atlower inner-particle cohesion values for higher dynamical optical depth. We present an analysis of the physicaloptical depth, particle number density, and structure characteristics in the simulations at equilibrium. For highcohesion values, energy injection from differential shear causes transient large structures to rotate and collide athigh speed, breaking them apart, ultimately limiting the clump size and frustrating the formation of shear-freezones.
关键词：planets and satellites: dynamical evolution and stability;planets and satellites: rings
