Stable charged-particle acceleration and focusing in a laser accelerator using spatial harmonics.

Area of Science:

• Plasma Physics
• Particle Acceleration
• Laser-Plasma Interactions

Background:

• Laser-driven acceleration of charged particles is a promising technology.
• Achieving simultaneous transverse and longitudinal stability at non-ultrarelativistic energies remains a significant challenge.
• Earnshaw's theorem poses limitations, indicating defocusing effects from synchronous accelerating waves at these energies.

Purpose of the Study:

• To present a novel scheme for laser-driven particle acceleration.
• To overcome the limitations of simultaneous transverse and longitudinal stability at non-ultrarelativistic energies.
• To demonstrate the feasibility of this scheme for compact laser accelerators.

Main Methods:

• Utilizing interaction with a resonant spatial harmonic for acceleration.
• Employing strong ponderomotive interaction with nonresonant spatial harmonics for focusing.
• Analyzing the stability properties of the proposed scheme.

Main Results:

• The proposed scheme achieves net transverse focusing.
• The scheme demonstrates longitudinal stability for the accelerated particles.
• The method is shown to be applicable for compact laser accelerator designs.

Conclusions:

• This novel scheme effectively addresses the challenge of simultaneous transverse and longitudinal stability in laser-driven particle acceleration at non-ultrarelativistic energies.
• The findings pave the way for the development of more compact and efficient laser accelerators.
• The use of resonant and nonresonant laser harmonics offers a viable solution to overcome Earnshaw's theorem limitations.