High energy proton micro-bunches from a laser plasma accelerator

Area of Science:

• Plasma Physics
• Laser-Particle Acceleration
• Accelerator Physics

Background:

• Laser-driven ion accelerators show promise for applications in high energy physics and medicine.
• Existing methods face challenges in achieving high energy and monochromaticity.
• Novel acceleration mechanisms are needed to advance the field.

Purpose of the Study:

• To identify and demonstrate a new ion acceleration mechanism.
• To generate high-energy, monochromatic proton micro-bunches using laser-plasma interactions.
• To explore the potential for compact and efficient laser-driven accelerators.

Main Methods:

• Particle-in-cell (PIC) simulations were employed to model the interaction.
• An ultra-intense (2 PW, 20 fs) laser pulse interacted with a dual-gas target (mixed C & H species).
• Near-critical-density partially ionized plasmas were used.

Main Results:

• Generation of high-energy monochromatic proton micro-bunches (peak energy 350 MeV).
• Observed acceleration and self-modulation of the proton beam.
• Achieved high quality beams with laser to proton conversion efficiency of ~10^-4 and low angular divergence (<10 degrees).

Conclusions:

• The novel mechanism enables high-quality proton beam generation relevant for medical applications.
• This scheme can enhance energy and monochromaticity, potentially reducing accelerator size.
• Mixed-gas targets facilitate high repetition rate operation, free from plasma debris and EMP disruptions.