Fluids at high dynamic pressures and temperatures

Abstract

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First-principles equation of state calculations of warm dense nitrogen

“…Such experiments are often used to determine the principal Hugoniot curve, which is the locus of final states that can be obtained from different shock velocities. A number of Hugoniot measurements have been made for nitrogen 7,[41][42][43][45][46][47] . Density functional theory has been validated by experiments as an accurate tool for predicting the shock compression of a variety of different materials 106,107 , including nitrogen 58,59 .…”

“…In the condensed matter regime, nitrogen is capable of forming a wide variety of triple-, double-, and single-bonded compounds, which makes it of interest to geological and energy sciences. At higher densities and temperatures, nitrogen exists as a molecular fluid that undergoes a pressure-induced dissociation transition to polymeric and atomic fluids of interest in planetary science [7][8][9] . In the warm dense matter (WDM) regime, nitrogen exists in partially ionized plasma states, which are of fundamental interest to shock physics and astrophysics communities.…”

“…2). Several experimental measurements of dense, liquid nitrogen states have been performed using dynamic shock compression experiments 7,[40][41][42][43][44][45][46][47] , with the most extreme ones reaching up to a pressure of 180 GPa 47 and a temperature of 14,000 K 7 . The main focus of these experiments was to understand the shock-induced dissociation of molecular nitrogen at 30-80 GPa on the Hugoniot curve, as reviewed by Ross 1 and Nellis 2 .…”

Shock compression of simple liquids: Implications for deuterium

“…In contrast, shock-compressed liquid nitrogen shows a considerable softening of the Hugoniot above 0.3Mbar and 7000K [24], believed to be the result of molecular dissociation.…”

Proton Diffusion in Ice Bilayers

“…Such a superionic phase can be characterized as a partially melted state and compared with an ionic fluid or a fully melted state in which neutral or ionized water molecules diffuse freely. The superionic phase of ice may play a crucial role in the generation of the magnetic fields in giant planets as well as their metallic fluid [14][15][16][17] The experimental fact of the small diffusion rate at ambient pressure and the theoretical prediction of a superprotonic state under extreme conditions point us to diffusion measurements for "hot ice" in which protons are thermally activated to move faster. The high pressure techniques enable us to generate an extreme condition around 1000 K and 20 GPa where ice is predicted to enter the superprotonic state.…”