Robust Autoresonant Excitation in the Plasma Beat-Wave Accelerator: A Theoretical Study

A modified version of the Plasma Beat-Wave Accelerator scheme is presented, which is based on autoresonant phase-locking of the nonlinear Langmuir wave to the slowly chirped beat frequency of the driving lasers via adiabatic passage through resonance. Compared to traditional approaches, the autoresonant scheme achieves larger accelerating electric fields for given laser intensity; the plasma wave excitation is more robust to variations in plasma density; it is largely insensitive to the details of the slow chirp rate; and the quality and uniformity of the resulting plasma wave for accelerator applications may be superior.