One-dimensional model for chemotaxis with hard-core interactions

Velocity jump process with volume exclusions in a narrow channel

This paper analyzes the impact of collisions in a system of N identical hard-core particles driven according to a velocity jump process. The physical space is essentially a channel in R with a probability of occupants being able to pass each other. The system mimics what nature does, where individuals pass one another in a narrow channel while making incidental contact with those moving in the opposite direction. The passing probability may depend on the particles' size and the channel's width. Starting from the particle level model, we systematically derive a nonlinear transport equation based on an asymptotic expansion. Under low-occupied fractions, numerical solutions of both the kinetic model and the stochastic particle system are compared well during biased and unbiased random velocity changes. Analysis of the subpopulation motility within a large population exhibits the consequences of volume exclusions and channel confinements on the traveling speeds.