Run-and-tumble dynamics of self-propelled particles in confinement

Run-and-tumble dynamics is a wide-spread mechanism of swimming bacteria. The accumulation of run-and-tumble microswimmers near impermeable surfaces is studied theoretically and numerically in the low-density limit in two and three spatial dimensions. Both uni-modal and exponential distributions of the run lengths are considered. Constant run lengths lead to peaks and depletions regions in the density distribution of particles near the surface, in contrast to exponentially distributed run lengths. Finally, we present a universal accumulation law for large channel widths, which applies not only to run-and-tumble swimmers, but also to many other kinds of self-propelled particles. Copyright (C) EPLA, 2015