Dispersion and damping of potential surface waves in a degenerate plasma

Potential (electrostatic) surface waves (SWs) in a semi-bounded plasma with degenerate electrons are studied using the quasi-classical mean-field kinetic model. The SW spectrum and the collisionless damping rate are obtained numerically for a wide range of wavelengths. In the limit of long wavelengths, the SW frequency omega approaches the cold-plasma limit omega = omega(p)/root 2 p with omega(p) being the plasma frequency, while at short wavelengths, the SW spectrum asymptotically approaches the spectrum of zero-sound mode propagating along the boundary. It is shown that the surface waves in this system remain weakly damped at all wavelengths (in contrast to strongly damped surface waves in Maxwellian electron plasmas), and the damping rate nonmonotonically depends on the wavelength, with the maximum (yet small) damping occurring for surface waves with wavelength of approximate to 5 pi lambda(F), where lambda(F) is the Thomas-Fermi length. The applicability of the used approximations and of the obtained results is discussed in detail. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3690098]