Magnetoplasma surface waves in solids with diffuse electron density profiles

Magnetoplasma surface waves in metals and semiconductors have, up to the present, been studied within the framework of a local theory of electronic conduction. With a nonlocal theory of conduction additional surface excitations referred to as "higher-multipole" excitations can occur for sufficiently diffuse electron density profiles. The dependence on the orientation and strength of an applied magnetic field of the regular surface magnetoplasmon and of the higher-multipole excitations is studied within the framework of hydrodynamics. The sensitivity of the higher multipoles to the orientation of the applied field may be a useful tool in the identification of these modes.