# Numerical Simulations of Saturn's B Ring: Granular Friction as a Mediator between Self-Gravity and Viscous Overstability

## TL;DR

This study uses advanced particle collision modeling to explore how granular friction influences the formation of structures in Saturn's B ring, revealing that particle surface roughness determines whether self-gravity wakes or viscous overstability dominate.

## Contribution

It introduces a new particle collision method to analyze the effects of granular friction on ring structure formation, highlighting the role of particle surface properties.

## Key findings

- Rough particles favor viscous overstability features.
- Smooth particles tend to form self-gravity wakes.
- Granular friction mediates the dominance of different ring structures.

## Abstract

We study the B ring's complex optical depth structure. The source of this structure may be the complex dynamics of the Keplerian shear and the self-gravity of the ring particles. The outcome of these dynamic effects depends sensitively on the collisional and physical properties of the particles. Two mechanisms can emerge that dominate the macroscopic physical structure of the ring: self-gravity wakes and viscous overstability. Here we study the interplay between these two mechanisms by using our recently developed particle collision method that allows us to better model the inter-particle contact physics. We find that for a constant ring surface density and particle internal density, particles with rough surfaces tend to produce axisymmetric ring features associated with the viscous overstability, while particles with smoother surfaces produce self-gravity wakes.