The effects of screening parameter on Edgemagnetoplasmons

We report a study of dependence of Edgemagnetoplasmons on screening parameter on a helium surface. A finite field is used since it is difficult to extract the signal from crossing of many right and left handed edge modes near zero magnetic field. We find that the change in frequency is in agreement with a change in electron pool radius. A qualitative comparison between our experimental results and theory is given.