Laser shock measurements revise diamond melting temperature at megabar pressures
Dynamic laser compression experiments reveal that diamond melts at temperatures differing by more than 700 °C from earlier experimental estimations. By tracking phase boundaries under extreme megabar loading, researchers successfully resolved persistent discrepancies in high-pressure carbon modeling, establishing vital empirical constraints for inertial confinement fusion capsule engineering and planetary interior structure simulations.
Science··Morning
Observing carbon phase transitions with ultrafast laser pulses
To investigate high-pressure carbon thermodynamics under planetary conditions, physicists exposed synthetic diamond samples to high-intensity ultraviolet laser pulses. The generated compression wave subjected the crystal lattice to extreme megabar loading, driving the material across its transition boundary into a metallic liquid phase while in situ diagnostics recorded sudden changes in optical reflectivity across the shocked sample surface during the brief shock interval.[1]
Correcting the melting temperature discrepancy in carbon models
The experimental findings demonstrated that carbon transition occurs at temperatures differing by more than 700 °C from earlier estimations. These direct measurements successfully resolved long-standing inconsistencies in high-pressure carbon phase calculations, aligning laboratory observations with quantum molecular dynamics simulations without requiring unverified intermediate solid phases or exotic chemical bonding configurations.[1]
Guiding fusion capsule design and planetary interior models
Accurate melting curve benchmarks provide foundational empirical constraints for inertial confinement fusion capsules, where diamond ablator shells must maintain hydrodynamic stability during intense laser compression. Furthermore, the refined carbon equation of state improves interior structure models for ice giant planets, clarifying how liquid carbon layers behave within dense celestial mantles during long evolutionary timescales.[1]
