Laser-plasma acceleration beyond wave breaking

Laser wakefield accelerators rely on the extremely high electric fields of nonlinear plasma waves to trap and accelerate electrons relativistic energies over short distances. When driven strongly enough, break, trapping a large population background that support their motion. Aside from limiting maximum field, this can lead accelerated electron bunches with energy spreads. Here, we introduce novel regime wave excitation acceleration allows for arbitrarily while avoiding deleterious effects unwanted trapping. The regime, enabled by spatiotemporal shaping laser pulses, exploits property superluminal phase velocities cannot charged particles are therefore immune breaking.