Breaking the dephasing and depletion limits of laser-wakefield acceleration with Traveling-Wave Electron Acceleration

We show how to simultaneously solve several long standing limitations of laser-wakefield acceleration that have thus far prevented laser-plasma electron accelerators (LWFA) to extend into the energy realm beyond 10 GeV. Most prominently, our novel Traveling-Wave Electron Acceleration (TWEAC) approach eliminates both the dephasing and depletion constraints. The wakefield driver is a region of overlap of two obliquely incident, ultrashort laser pulses with tilted pulse-fronts in the line foci of two cylindrical mirrors, aligned to coincide with the trajectory of subsequently accelerated electrons. TWEAC leads to quasistatic acceleration conditions, which do not suffer from laser self-phase modulation, parasitic self-injection or other plasma instabilities. Particularly, and in contrast to LWFA and PWFA, a single TWEAC-stage can arbitrarily be extended in length to higher electron energies without changing the underlying acceleration mechanism. We introduce the new acceleration scheme, show results from 3D particle-in-cell simulations using PIConGPU, discuss energy scalability for both laser and electrons and elaborate on experimental realization requirements.