Time-resolved soft x-ray spectra from laser-produced Cu plasma

Area of Science:

• Plasma Physics
• Laser-Matter Interaction
• Atomic Physics

Background:

• Volumetric heating of materials is crucial for applications like inertial confinement fusion.
• Understanding laser-plasma interactions requires accurate characterization of material response.
• Previous studies have focused on surface effects, necessitating investigation into bulk heating dynamics.

Purpose of the Study:

• To experimentally and computationally investigate the volumetric heating of a thin copper target.
• To characterize the bulk heating of the copper target using time-resolved X-ray spectroscopy.
• To compare experimental soft X-ray emission spectra with radiation hydrodynamic simulations.

Main Methods:

• Utilized the Compact Multipulse Terawatt (COMET) laser to generate plasma for heating a thin copper target.
• Employed time-resolved X-ray spectroscopy with a variable spaced grating spectrometer and X-ray streak camera to measure soft X-ray emission (800-1550 eV).
• Performed two-dimensional radiation hydrodynamic simulations using the HYDRA code, followed by atomic kinetics post-processing with CRETIN to generate synthetic spectra.

Main Results:

• Experimental soft X-ray emission spectra were compared with synthetic spectra generated from simulations.
• The comparison indicated the presence of specific copper ionization states.
• Derived electron temperatures and ion densities throughout the laser-heated copper target.

Conclusions:

• The study successfully characterized the bulk heating of a laser-irradiated copper target.
• Experimental data validated the accuracy of the HYDRA and CRETIN codes for simulating laser-plasma interactions.
• The findings provide insights into the ionization states and plasma conditions within laser-heated materials.