Self-Propagating Patterns in Active Filament Bundles

Bundles of polar filaments which interact via active elements can exhibit complex dynamic behaviors. By using a simple and general description for the bundle dynamics, we find regimes for which density profiles propagate as solitary waves with a characteristic velocity along the bundle. These behaviors emerge from an interplay of local contractions in the bundle and relative sliding of oppositely oriented filaments. By introducing filament binding to and detachment from a substrate, the system is able to generate net motion as a self-organization phenomenon.