Features of the Debye mode in an electron plasma at various degrees of the electron gas degeneracy

We have considered the response of an electron plasma with an arbitrary degree of degeneration to an alternating electromagnetic field directed perpendicularly to the boundary of the plasma layer. The plasma screening of the electric field is determined by the Debye mode. The analysis of the behavior of this mode has been carried out depending on the parameters of the problem. For the first time, it has been shown that, ar sufficiently high degrees of the electron gas degeneracy, the range of the Debye mode existence has a substantially nontrivial character, in which the ranges of existence and absence of this mode alternate with increasing electric field frequency.