Parabolic Plasma Sheath Potentials and their Implications for the Charge on Levitated Dust Particles

Analysis of several numerical plasma sheath models, as well as data from several previously reported experiments, is shown to indicate that the sheath potential function may often be very closely approximated with a parabola. We also demonstrate that once this potential function is suitably determined the charge on isolated dust particles levitated in the plasma sheath may be calculated directly from their equilibrium heights.