Polarized electron acceleration in beam-driven plasma wakefield based on density down-ramp injection.

Area of Science:

• Plasma physics
• Particle acceleration
• Quantum mechanics

Background:

• Plasma wakefield acceleration (PWFA) is a promising particle acceleration technique.
• Generating polarized electron beams is crucial for fundamental physics research and applications.
• Preserving electron spin polarization during acceleration is a significant challenge.

Purpose of the Study:

• To investigate electron spin precession in beam-driven PWFA with density down-ramp injection.
• To establish criteria for maintaining high electron polarization during acceleration.
• To explore the advantages of electron-beam drivers over laser drivers for polarized electron generation.

Main Methods:

• Full three-dimensional (3D) particle-in-cell (PIC) simulations.
• Single-particle modeling.
• Analysis of driving beam parameters and injected beam flux.

Main Results:

• Criteria for driving beam parameters and injected beam flux were derived to preserve high electron polarization.
• 3D PIC simulations and single-particle modeling confirmed these criteria.
• Electron-beam drivers eliminate prepulse-induced depolarization issues inherent in laser drivers.

Conclusions:

• Beam-driven PWFA with density down-ramp injection can generate highly polarized electron beams.
• The derived criteria provide essential guidance for experimental design.
• This method offers a viable pathway for creating novel polarized electron sources for future research.