Nonisentropic Release of a Shocked Solid

PG Heighway and M Sliwa and D McGonegle and C Wehrenberg and CA Bolme and J Eggert and A Higginbotham and A Lazicki and HJ Lee and B Nagler and HS Park and RE Rudd and RF Smith and MJ Suggit and D Swift and F Tavella and BA Remington and JS Wark, PHYSICAL REVIEW LETTERS, 123, 245501 (2019).

DOI: 10.1103/PhysRevLett.123.245501

We present molecular dynamics simulations of shock and release in micron-scale tantalum crystals that exhibit postbreakout temperatures far exceeding those expected under the standard assumption of isentropic release. We show via an energy-budget analysis that this is due to plastic-work heating from material strength that largely counters thermoelastic cooling. The simulations are corroborated by experiments where the release temperatures of laser-shocked tantalum foils are deduced from their thermal strains via in situ x-ray diffraction and are found to be close to those behind the shock.

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