Influence of plasma screening on high-density inverse bremsstrahlung absorption

Area of Science:

• Plasma physics
• Fusion energy research

Background:

• Plasma screening effects are crucial for understanding energy absorption in high-density plasmas.
• Previous studies suggested a more restrictive screening length, impacting inverse bremsstrahlung absorption models.

Purpose of the Study:

• To investigate the impact of plasma screening on inverse bremsstrahlung absorption using a novel diagnostic.
• To determine the appropriate screening length for high-density inverse bremsstrahlung absorption.

Main Methods:

• Utilized a spherical-implosion platform equipped with the "beamlets" scattered-light detector for high-sensitivity measurements.
• Analyzed experimental data to assess the influence of plasma screening on energy absorption processes.

Main Results:

• Beamlets data indicate the electron-only Debye length is the relevant screening length for high-density inverse bremsstrahlung absorption.
• Contradicts previous suggestions of a more restrictive screening length.

Conclusions:

• The updated absorption model, incorporating the electron-only Debye length, accurately reproduces OMEGA direct-drive inertial confinement fusion implosion database bang times.
• Eliminates the need for ad hoc multipliers in fusion simulations.