Shock Compression of Liquid Deuterium up to 1 TPa

Area of Science:

• High-energy-density physics
• Condensed matter physics
• Materials science

Background:

• Deuterium's properties under extreme pressure are crucial for understanding planetary interiors and inertial confinement fusion.
• Accurate equations of state (EOS) for deuterium are essential for theoretical modeling and experimental validation.

Purpose of the Study:

• To experimentally determine the Hugoniot and reflected-shock properties of cryogenic liquid deuterium up to 1 TPa.
• To compare experimental compression data with state-of-the-art ab initio calculations and existing EOS models.
• To identify limitations of current theoretical models in describing deuterium behavior at extreme pressures.

Main Methods:

• Laser-driven shock compression of cryogenic liquid deuterium.
• High-precision interferometric Doppler velocimetry for precise shock velocity measurements.
• Impedance-matching analysis to determine material compression.

Main Results:

• Experimental data reveal significant deviations from theoretical predictions beyond 250 GPa along the principal Hugoniot.
• First-principles models predict a stiffer response than observed experimentally above 250 GPa.
• Reflected shock data above 500 GPa show 5%-7% higher compression than predicted by all current EOS models.
• Density functional theory calculations accurately predict compression in the molecular-to-atomic transition range.

Conclusions:

• No single EOS model accurately describes deuterium's principal Hugoniot across the entire experimental pressure range.
• Current first-principles models require refinement to match experimental deuterium compression data at multi-TPa pressures.
• Experimental data provide critical benchmarks for improving theoretical understanding of matter under extreme conditions.