In Situ Measurement of Electron Energy Evolution in a Laser-Plasma Accelerator.

Area of Science:

• Plasma Physics
• Accelerator Physics
• Laser-Plasma Interactions

Background:

• Laser-plasma accelerators (LPAs) offer a promising alternative to conventional accelerators.
• Accurate measurement of electron beam properties and acceleration fields is crucial for LPA development.
• Existing methods can be invasive or lack sufficient spatial resolution.

Purpose of the Study:

• To introduce a novel, noninvasive method for measuring electron beam energy evolution in LPAs.
• To enable in-situ detection of acceleration fields without perturbing the electron beam.
• To validate the method against established simulation techniques.

Main Methods:

• Utilizing Thomson scattering for high spatial resolution measurements.
• Applying the technique to probe electron beam energy within a laser-plasma accelerator.
• Analyzing the data to infer local electron energy and acceleration field strength.

Main Results:

• Demonstrated in-situ measurement of electron beam energy evolution.
• Quantified the decrease in accelerating fields from (265±119) GV/m to (9±4) GV/m in a plasma density ramp.
• Achieved excellent agreement between experimental data and particle-in-cell simulations.

Conclusions:

• The developed Thomson scattering method is a powerful tool for diagnosing LPAs.
• This technique allows for the study of acceleration field dynamics.
• It opens new avenues for the optimization and advancement of plasma-based accelerators.