The first-order phase transition as a result of the parametric action of a thermal field

The dynamics of an infinite chain of like particles linked both to each other and to a certain immobile base (a chain of bound oscillators) is considered. The chain of oscillators occurs in a variable and spatially inhomogeneous thermal electromagnetic field inducing significant fluctuations in the shape of potential of the interparticle interaction. It is shown that the field action renders the bound oscillators a parametric system pumped by the thermal field. An increase in the temperature (accompanied by an increase in the spectral density and frequency range of the thermal field) leads to an increase in the relaxation time of oscillators and eventually to their self-excitation. A condition of the corresponding first-order phase transition is obtained.