Title: Clustering of Magnetic Swimmers in a Poiseuille Flow,
Abstract: We investigate the collective behavior of magnetic swimmers, which are
suspended in a Poiseuille flow and placed under an external magnetic field,
using analytical techniques and Brownian dynamics simulations. We find that the
interplay between intrinsic activity, external alignment, and magnetic
dipole-dipole interactions leads to longitudinal structure formation. Our work
sheds light on a recent experimental observation of a clustering instability in
this system.