2-D plasma dust crystal compression in a parabolic well

A spherically curved (locally parabolic) electrode with a conformal plasma sheath can be used to directly test two-dimensional (2-D) plasma crystal particle-particle interaction models and to derive the screening length and the charge on the particles. By using such a well, the lateral interaction potential was isolated and accessible. Good agreement was obtained between measured and calculated single particle trajectories using measured gas densities and temperatures to determine the neutral gas drag. Plasma crystal compression in the parabolic potential was demonstrated to be in good agreement with that predicted by an equation of state for the 2-D dust layer incorporating Debye shielding of the charges.