Bremsstrahlung cannon design for shock ignition relevant regime

Area of Science:

• Plasma Physics
• High-Energy-Density Physics
• Laser-Plasma Interactions

Background:

• Laser-driven fast electron populations are crucial in inertial confinement fusion schemes like shock ignition.
• Understanding electron energy distributions is key to controlling energy transfer and implosion dynamics.
• Stimulated Raman Scattering (SRS) and Two Plasmon Decay (TPD) are primary instabilities generating these fast electrons.

Purpose of the Study:

• To optimize the BremsStrahlung Cannon (BSC) design for investigating fast electron populations.
• To differentiate X-ray emission contributions from SRS and TPD-generated fast electrons.
• To analyze fast electron temperatures of 40 keV (SRS) and 95 keV (TPD) via bremsstrahlung.

Main Methods:

• Experimental campaign at the Laser Megajoule-PETawatt Aquitaine Laser facility.
• Utilized a BremsStrahlung Cannon (BSC) for X-ray detection and analysis.
• Reconstruction of incident X-ray photon distributions on the BSC.

Main Results:

• Successful optimization of the BSC for the specified experimental conditions (10^15–10^16 W/cm²).
• Methodology established for analyzing X-ray emission originating from fast electrons.
• Framework developed for reconstructing X-ray photon distributions incident on the detector.

Conclusions:

• The optimized BSC is a viable tool for studying fast electron dynamics in laser-plasma interactions.
• The study provides a pathway to disentangle contributions from different plasma instabilities to X-ray emission.
• This research advances the understanding of electron acceleration mechanisms relevant to shock ignition.