Laser-cluster interaction: x-ray production by short laser pulses

Area of Science:

• Atomic and Molecular Physics
• Plasma Physics
• Laser-Matter Interactions

Background:

• Understanding electron heating in large atomic clusters is crucial for laser-driven processes.
• Previous studies have explored various heating mechanisms, but efficient processes in large clusters remain an active research area.

Purpose of the Study:

• To investigate the heating mechanisms of quasifree electrons in large rare-gas clusters exposed to short laser pulses.
• To identify and quantify the role of elastic large-angle backscattering in electron heating.

Main Methods:

• Utilized a mean-field classical transport simulation to model electron dynamics.
• Simulated electron-impact ionization, collective electron motion, and cluster charging effects.
• Compared simulation results for X-ray yields with experimental data.

Main Results:

• Identified elastic large-angle backscattering of electrons at ionic cores as an efficient laser-driven heating mechanism.
• The simulation results for absolute X-ray yields showed quantitative agreement with recent experimental findings.
• Investigated the influence of collective electron motion, ionization, and charging on the heating process.

Conclusions:

• Elastic electron backscattering is a key mechanism for heating quasifree electrons in large rare-gas clusters.
• The classical transport model accurately reproduces experimental X-ray yields, validating the identified heating mechanism.