Is the electrostatic force between a point charge and a neutral metallic object always attractive?

Abstract

We give an example of a geometry in which the electrostatic force between a point charge and a neutral metallic object is repulsive. The example consists of a point charge centered above a thin metallic hemisphere, positioned concave up. We show that this geometry has a repulsive regime using both a simple analytical argument and an exact calculation for an analogous two-dimensional geometry. Analogues of this geometry-induced repulsion can appear in many other contexts, including Casimir systems.

7 pages, 7 figures

References in corpus (3)

• Casimir repulsion between metallic objects in vacuum
• Constraints on stable equilibria with fluctuation-induced forces
• Is the electrostatic force between a point charge and a neutral metallic object always attractive?

Cited by in corpus (4)

• Casimir-Polder repulsion: Polarizable atoms, cylinders, spheres, and ellipsoids
• Is the electrostatic force between a point charge and a neutral metallic object always attractive?
• Geometrical dependence in Casimir-Polder repulsion: Anisotropically polarizable atom and anisotropically polarizable annular dielectric
• Boundary Effects on Ideal Fluid Forces and Kelvin's Minimum Energy Theorem