Demonstrate high-charge, high-efficiency acceleration over substantial distance in PWFA

Demonstrate acceleration of a large amount of electron-beam charge with high efficiency over a substantial distance in plasma wakefield acceleration, establishing the feasibility of sustained high-efficiency energy transfer for applications such as free-electron lasers and electron–positron colliders.

Background

Plasma wakefield acceleration (PWFA) has achieved several milestones, including multi-GV/m gradients, high-efficiency acceleration, and emittance preservation in specific configurations. However, the field still lacks an experimental demonstration that simultaneously achieves large accelerated charge, high efficiency, and significant acceleration length—key requirements for future collider and FEL applications.

The E302 experiment at FACET-II is motivated in part by this gap, aiming to measure efficiency, quantify transverse instability effects, and test mitigation strategies, thereby contributing to the broader goal of demonstrating practical, scalable PWFA performance.