Spatiotemporal Behavior of Void Collapse in Shocked Solids

TL;DR

This study uses molecular dynamics simulations to analyze how void collapse in shocked solids generates hot spots, revealing the dynamics of temperature and energetic particle behavior during collapse.

Contribution

It provides detailed insights into the spatiotemporal behavior of void collapse and introduces a new measure of shock-enhanced chemistry intensity based on colliding particles.

Findings

Maximum colliding particles occur after void collapse completion.

Temperature peaks earlier than colliding particle count during collapse.

Velocity and temperature of ejected molecules increase during collapse.

Abstract

Molecular dynamics simulations on a three dimensional defective Lennard-Jones solid containing a void are performed in order to investigate detailed properties of hot spot generation. In addition to the temperature, I monitor the number of energetically colliding particles per unit volume which characterizes the intensity of shock-enhanced chemistry. The quantity is found to saturate for nanoscale voids and to be maximized after voids have completely collapsed. It makes an apparent comparison to the temperature which requires much larger void for the enhancement and becomes maximum during the early stage of the collapse. It is also found that the average velocity and the temperature of ejected molecules inside a cubic void are enhanced during the collapse because of the focusing of momentum and energy towards the center line of a void.