Two-color hybrid laser wakefield and direct laser accelerator

We propose and investigate the concept of two-color laser wakefield and direct acceleration (LWDA) scheme in the regime of moderate (10 TW scale) laser powers. The concept utilizes two unequal frequency laser pulses: the leading long-wavelength (λ0 = 0.8 µm) wakefield laser pulse driving a nonlinear plasma wake, and a trailing short-wavelength (λDLA = λ0/2) DLA laser pulse. The combination of the large electric field, yet small ponderomotive pressure of the DLA pulse is shown to be advantageous for producing a higher energy and larger charge electron beam compared with the single frequency LWDA. The sensitivity of the dual-frequency LWDA to synchronization time jitter is also reduced.