Simulations show dynamical heterogeneity at moderate shock intensities in Yukawa solids

Yukawa systems, like dusty plasmas, are highly studied due to their ability to model various kinetic processes. Shocks in such systems are valuable subjects of study due to their potential to induce phase shifts. Feng et al. detailed the post-shock separation of solid- and liquid-like phases in 2D Yukawa solids using molecular dynamics simulations.

The researchers found shocks within a certain range of compressional speed results in partial melting, with the solid-state existing close to the shock boundary and liquid beyond it. In this case, the temperature close to the boundary is lower than the typical post-shock region.

“We attribute this spatial variation of the kinetic temperature to the dynamical heterogeneity of the 2D Yukawa systems,” said author Yan Feng. “Which is most severe when the compressional shock is just barely able to melt the 2D Yukawa solid.”

The systems in this study were simulated using large-scale atomic/molecular massively parallel simulator. To attain their results, the researchers ran simulations utilizing three different shock speeds—high speed shocks that completely melted the solid, low speed shocks in which solidity was maintained, and the moderate shock speed allowing solid-liquid coexistence.

The scientists reveal dynamical heterogeneity in the phase transition has a notable impact on these systems. However, the structural and dynamical properties after shock propagation must be detailed further.

“We think the possible subjects of our next compressional shock research include the detailed kinetics around shock fronts and post-shock evolution related to its internal stress,” Feng said.

Source: “Observation of the solid and liquid separation after the shock propagation in a two-dimensional Yukawa solid,” by Pengwei Qiu, Tianyue Sun, and Yan Feng, Physics of Plasmas (2021). The article can be accessed at https://doi.org/10.1063/5.0067155 .