Recombination effects in laser-driven acceleration of heavy ions

Area of Science:

• Plasma Physics
• Atomic Physics
• Laser-Plasma Interactions

Background:

• High-intensity lasers interacting with solid targets accelerate heavy ions.
• Understanding ion charge-state distributions is crucial for applications like heavy-ion fusion and medical isotope production.
• Recombination processes can influence the final charge states of accelerated ions.

Purpose of the Study:

• To investigate the role of recombination effects on heavy ion charge-state distributions in laser-driven acceleration.
• To develop and implement a recombination package for particle-in-cell (PIC) codes.
• To model a specific experiment involving high-intensity laser pulses interacting with gold targets.

Main Methods:

• Development of a recombination package incorporating dielectronic, radiative, and three-body recombination for PIC codes.
• One-dimensional PIC simulations of laser-solid interactions with thin gold targets.
• Comparison of simulation results with experimental observations of gold ion beams.

Main Results:

• Simulations showed recombination did not affect ion beams from 100-nm targets.
• Recombination led to reduced charge states in ion beams from 300-nm targets, consistent with experimental data.
• The observed differences were attributed to target temperature variations, affecting the dominance of recombination over ionization.

Conclusions:

• Recombination is a key factor modifying heavy ion charge states in laser-driven acceleration.
• Target thickness and resulting temperature play a critical role in determining the significance of recombination effects.
• The developed recombination package accurately models experimental observations in laser-plasma interactions.