Effect of Nonreciprocal Forces on Brownian Motion of Plasma Crystal

The effect is studied theoretically of nonreciprocity of interparticle forces on the Brownian motion of a single-layer plasma crystal with the hexagonal lattice. The interaction potential used is the potential of a point charge in plasma consisting of the Maxwellian electrons and directed flow of cold ions. It is shown that in the spectral density of particle displacements, there is a large number of singularities that occur due to the presence of critical points at frequencies corresponding to different oscillation branches. When approaching the threshold for developing the instability of coupled waves, the synchronous correlation matrices of velocities indicate the considerable deviation from the law of kinetic energy equipartition over degrees of freedom.