Electrostatics of two charged conducting ellipsoids

Predictions of the electrostatic force (EF) for charged conducting spheres have been made previously using first-principles electrostatics [J. Lekner, Meas. Sci. Technol. 23, 085007 (2012)]. Here, finite element calculations of EF are presented for a variety of conducting ellipsoids differing with respect to size, gap distance, orientation, and shape. The results are expressed in terms of directly measurable experimental parameters. Our results are consistent with those of Lekner, namely, that charged ellipsoids exhibit mutual repulsion at all distances when they have the same charging potential, otherwise EF becomes attractive when the gap distance between the two ellipsoids is close enough. Additionally, we analyze the relationship between short-range attraction, capacitance, and EF in detail. The complexity of the electrostatic response on both external and material parameters suggests applications not only in electrostatics but in plasmonics and biosensor devices as well.