Particle with internal dynamical asymmetry: chaotic self-propulsion and turning

We investigate model of a complex particle that consists of a rigid shell and a nucleus with spatial asymmetric interaction. The particle's dynamics with the nucleus driven by a time-periodic force is considered. It is shown that unidirectional self-propulsed motion of particle arises in the absence of spatial and temporary asymmetry of external potentials and influences. Transport regimes are generic for the particle dynamics in the presence of nonlinear friction or periodic external potential. The changes of transport velocity and direction are determined by qualitative changes of dynamics regimes: attractor bifurcations in the internal phase space of the complex particle. Finally, microbiological relevance of the proposed model is briefly discussed. (C) 2002 Published by Elsevier Science B.V.