Undepleted direct laser acceleration

Area of Science:

• High-energy physics
• Laser-plasma interactions
• Particle acceleration

Background:

• Intense lasers are used to generate high-energy particle beams in laboratory settings.
• The direct laser acceleration (DLA) method utilizes laser pulses to ionize target material, creating a plasma channel for electron acceleration.
• DLA offers high energy conversion efficiency, making it suitable for generating photonuclear reactions.

Purpose of the Study:

• To investigate the role of target material atomic number in the efficiency of direct laser acceleration (DLA).
• To understand the mechanism of ionization electron injection during DLA.
• To optimize conditions for enhanced neutron yields in multi-petawatt laser experiments.

Main Methods:

• Experimental demonstration of DLA with varying target materials.
• Numerical simulations to model plasma channel formation and electron dynamics.
• Analysis of electron injection and acceleration efficiency based on target atomic number.

Main Results:

• A target material with a sufficiently high atomic number is necessary for sustained ionization electron injection.
• Low atomic number targets lead to premature depletion of ionization electrons, hindering efficient DLA.
• Experimental and numerical data confirm the correlation between target atomic number and DLA performance.

Conclusions:

• The atomic number of the target material is a critical parameter for efficient direct laser acceleration.
• Selecting high atomic number targets ensures optimal electron injection for maximizing photonuclear reactions.
• This finding is expected to significantly increase neutron yields in advanced multi-petawatt laser experiments.