  Multistage coupling of laser-wakefield accelerators is essential to overcome
laser energy depletion for high-energy applications such as TeV level
electron-positron colliders. Current staging schemes feed subsequent laser
pulses into stages using plasma mirrors, while controlling electron beam
focusing with plasma lenses. Here a more compact and efficient scheme is
proposed to realize simultaneous coupling of the electron beam and the laser
pulse into a second stage. A curved channel with transition segment is used to
guide a fresh laser pulse into a subsequent straight channel, while allowing
the electrons to propagate in a straight channel. This scheme benefits from a
shorter coupling distance and continuous guiding of the electrons in plasma,
while suppressing transverse beam dispersion. With moderate laser parameters,
particle-in-cell simulations demonstrate that the electron beam from a previous
stage can be efficiently injected into a subsequent stage for further
acceleration, while maintaining high capture efficiency, stability, and beam
quality.

Plasma Physics