Orbiting Dust Particles in a Potential Sheath

A variable aperture with a center post placed in a strongly-coupled complex plasma will generate a ring shaped potential. A dusty plasma ring is formed inside the confining potential well. A single dust particle that orbits around the ring is occasionally observed during the initial setup. Various parameters for the orbiting particle including the velocity, period, and mass can be calculated. Drag forces acting on the orbiting particle are discussed. A driving force allowing the particle to continuously orbit in the potential well is postulated.