Edgemagnetoplasmons in a partially screened two-dimensional electron gas

We report a study of edgemagnetoplasmons in a partially-screened system of electrons on a helium surface. We compare experimental results with theories of Fetter and of Mikhailov and Volkov on the frequency, damping, and penetration-depth dependence on magnetic field, temperature-dependent damping, and the dependence of the frequency on screening. We show explicitly the dependence of frequency on edge density profile.