Single-Shot Visualization of Evolving Plasma Wakefields.

We measure the evolution history of terawatt-laser driven plasma wakefields in the nonlinear bubble regime using an all-optical frequency-domain streak camera (FDSC) technique. The longitudinal profiles of the plasma "bubble" at different propagation distances within a 3 mm long ionized helium gas target are imaged in single shots, illustrating formation, propagation and coalescence of the bubble. 3D particle-in-cell (PIC) simulations validate the observed density-dependent bubble evolution, and correlate it with generation of a quasi-monoenergetic ~ 100 MeV electron beam. To visualize petawattlaser- or e-beam driven plasma wakefields, FDSC is extended to multi-object-plane imaging (MOPI) to measure evolution of wakefield transverse profiles over acceleration distance up to ~ 1 m in a single shot. [ABSTRACT FROM AUTHOR]