Dynamical formation of a nonequilibrium subsystem under severe action

TL;DR

This paper uses molecular dynamics simulations to study how nonequilibrium subsystems form and dissipate energy during defect generation, introducing a model with different temperatures and entropies for equilibrium and nonequilibrium states.

Contribution

It presents a novel simulation approach and a relaxation equation to describe the time evolution of nonequilibrium entropy during defect formation.

Findings

Dissipation of low-frequency acoustic energy into high-frequency vibrations observed.

Different temperatures and entropies assigned to equilibrium and nonequilibrium subsystems.

A simple relaxation equation effectively models the nonequilibrium entropy dynamics.

Abstract

Formation of the nonequilibrium subsystem in dynamical processes during defect generation is simulated by means of molecular dynamics. A particular process of dissipation of the low-frequency acoustic emission into high-frequency equilibrium vibrations of lattice is studied numerically. Clear heuristic reasons are used to introduce different temperatures and entropies for equilibrium and nonequilibrium subsystems. Simple relaxation equation is proposed to describe time behavior of the nonequilibrium entropy.