Electric-field distributions from densest packings of charged spheres in cylindrical confinement

Identical hard spheres in cylindrical confinement exhibit a variety of densest-packed columnar structures that vary with the corresponding cylinder-to-sphere diameter ratio D. Research in the past two decades has focused on the structural characteristics of such structures, and less attention has been paid to their physical properties. We have investigated theoretically the electric-field distributions from five types of such structures at D ∈ [1, 2], namely linear chain, planar zigzag, single helix, double helix, and achiral doublets, where each structure of interest is modelled as a spatial distribution of identical point charges at the sphere centers. For increasing radial distance, we observed a transition from a near-field distribution that depends sensitively on the micro-arrangement of particles, to a far-field limit that is equivalent to the electric-field distribution from a continuous line of charge, as quantified by a variation in the scaling behavior of the radial electric field. Our findings may open up new avenues for generating specific electric-field distributions through the manipulation of micro-arrangements of charged particles in quasi-one-dimensional confinement.