Design of dynamic Hohlraum opacity samples to increase measured sample density on Z

Area of Science:

• Plasma Physics
• Astrophysics
• Materials Science

Background:

• Opacity measurements are critical for modeling stellar interiors, particularly the solar radiation and convection zone boundary.
• Previous opacity data for iron was limited to electron densities significantly lower than those found at the solar boundary.

Purpose of the Study:

• To design and simulate improved foil samples for measuring iron opacity at higher densities.
• To achieve plasma conditions relevant to the solar radiation and convection zone boundary.

Main Methods:

• Utilized two-dimensional (2D) LASNEX simulations to model the heating and expansion of opacity samples.
• Employed dynamic Hohlraum radiation sources and inferred radiation temperature profiles using pinhole cameras, x-ray diodes, and bolometers.
• Simulated layered foil samples (magnesium, iron, plastic) under specific radiation conditions.

Main Results:

• The simulations indicate that increasing the thickness of the plastic backing is an effective method to increase the density of the opacity sample.
• Provided insights into the behavior of materials under extreme radiation conditions relevant to astrophysical plasmas.

Conclusions:

• The study successfully outlines a method for designing denser opacity samples for future experiments.
• The findings will contribute to more accurate measurements of iron opacity, enhancing solar models.