Oblique modulation of electron-acoustic waves in a Fermi electron-ion plasma

The oblique modulational instability (MI) of electron-acoustic waves (EAWs) in a quantum plasma whose components are two distinct groups of electrons (one inertial cold electrons and other inertialess hot electrons) and immobile ions is investigated, by using a quantum hydrodynamic model. The analysis is carried out through the derivation of the nonlinear Schrodinger equation for the modulated EAW packets. The effects of obliqueness, the quantum diffraction (H), and the equilibrium density ratio of the cold to hot electron component (delta) on the MI of EAWs are numerically examined. At quantum scales, these parameters are found to significantly modify the MI domain in the plane of wave number and the angle (theta) between the modulation and the propagation direction. The relevance of our results in astrophysical environments, as well as in intense laser-solid density plasma interaction experiments is discussed. (C) 2007 American Institute of Physics.