Influence of the laser prepulse on proton acceleration in thin-foil experiments

Area of Science:

• Plasma physics
• Laser-driven particle acceleration

Background:

• Laser prepulses from amplified spontaneous emission (ASE) are inherent in high-power laser systems.
• Understanding prepulse effects is crucial for optimizing laser-plasma interactions and particle acceleration.

Purpose of the Study:

• To investigate the influence of laser prepulse duration on proton acceleration in thin-foil experiments.
• To determine the relationship between target thickness, prepulse duration, and maximum proton energy.

Main Methods:

• Thin-foil targets were subjected to laser pulses with varying prepulse durations.
• Proton energies were measured to assess the impact of prepulse and target parameters.
• Analysis focused on the interplay between prepulse-induced plasma formation and acceleration mechanisms.

Main Results:

• Proton energy is highly sensitive to prepulse duration.
• An optimal target thickness exists, dependent on prepulse duration, for maximizing proton energy.
• Rear-side acceleration dominates at optimal thickness, yielding higher energies.
• Thinner targets suffer from prepulse-induced rear-side plasma, favoring less efficient front-side acceleration and lower energies.

Conclusions:

• Laser prepulse characteristics critically influence proton acceleration efficiency.
• Tailoring target thickness to prepulse duration is essential for achieving high-energy protons.
• Controlling ASE prepulses is vital for reproducible and enhanced laser-driven proton acceleration.