High-quality electron beams from beam-driven plasma accelerators by wakefield-induced ionization injection

Area of Science:

• Plasma Physics
• Accelerator Physics
• Particle Acceleration

Background:

• Beam-driven plasma accelerators offer a path to compact and powerful particle acceleration.
• Controlled injection of electrons into plasma wakefields is crucial for generating high-quality beams.

Purpose of the Study:

• To present a novel, simple strategy for controlled ionization-induced electron trapping in beam-driven plasma accelerators.
• To demonstrate the generation of high-quality witness electron bunches using this injection method.

Main Methods:

• Utilizing electric wakefields generated by a high-current-density electron beam in a plasma.
• Employing three-dimensional particle-in-cell simulations with the OSIRIS code.
• Introducing a dopant gas (neutral helium) into a plasma column to trigger ionization and trapping.

Main Results:

• Demonstrated controlled ionization and trapping of electrons within the accelerating wakefield phase.
• Generated high-quality electron bunches with a 1.5 kA peak current.
• Achieved a transverse normalized emittance of 1.5 μm and an uncorrelated energy spread of 0.3% on a GeV scale.
• Produced electron bunches with a few femtosecond duration.

Conclusions:

• The proposed ionization-induced trapping strategy is effective for generating high-quality electron bunches.
• This method offers a simple and direct way to control electron injection in plasma accelerators.
• The simulation results validate the principle for future experimental studies.