X-ray scattering measurements on imploding CH spheres at the National Ignition Facility

Area of Science:

• Plasma physics
• Materials science under extreme conditions
• X-ray science

Background:

• Understanding matter under extreme pressures is crucial for inertial confinement fusion research.
• Polystyrene is a key material in fusion targets, making its behavior under compression vital.
• Previous models for plasma ionization states may not accurately reflect extreme conditions.

Purpose of the Study:

• To perform spectrally resolved X-ray scattering measurements on highly compressed polystyrene.
• To investigate the carbon K-shell ionization state and plasma temperature at multi-TPa pressures.
• To evaluate the accuracy of existing ionization models under extreme compression.

Main Methods:

• Utilizing spectrally resolved X-ray scattering at the National Ignition Facility.
• Creating highly compressed polystyrene via spherically convergent shocks.
• Recording scattering data of line radiation at 9.0 keV from dense plasma.

Main Results:

• Demonstrated sensitivity of elastic scattering to carbon K-shell ionization.
• Constrained the temperature of the dense plasma.
• For six times compressed polystyrene, determined an average temperature of 86 eV and a carbon ionization state of 4.9.

Conclusions:

• The experimental results indicate that current ionization models need revision.
• The findings are critical for refining models used in high-energy-density physics.
• This study provides crucial data for understanding matter under extreme pressures.