Quantum electron-acoustic double layers in a magnetoplasma

Using a quantum magnetohydrodynamic (QMHD) model, the existence of small but finite amplitude quantum electron-acoustic double layers (QEADLs) is reported in a magnetized collisionless dense quantum plasma whose constituents are two distinct groups of cold and hot electrons, and the stationary ions forming only the neutralizing background. It is shown that the existence of steady state solutions of these double layers obtained from an extended Korteweg-de Vries (KdV) equation depends parametrically on the ratio of the cold to hot electron unperturbed number density (delta), the quantum diffraction parameter (H), the obliqueness parameter (l(z)), and the external magnetic field via the normalized electron-cyclotron frequency (Omega). It is found that the system supports both compressive and rarefactive double layers depending on the parameters delta and l(z). The effects of all these parameters on the profiles of the double layers are also examined numerically.