Plasma-driven ultrashort bunch diagnostic
  Ultrashort electron bunches are crucial for an increasing number of applications, however, diagnosing their longitudinal phase space remains a challenge. We propose a new method that harnesses the strong electric fields present in a laser driven plasma wakefield. By transversely displacing driver laser and witness bunch, a streaking field is applied to the bunch. This field maps the time information to a transverse momentum change and, consequently, to a change of transverse position. We illustrate our method with simulations where we achieve a time resolution in the attosecond range. 
I. Dornmair, C. B. Schroeder, K. Floettmann, B. Marchetti, and A. R.   Maier
physics.acc-ph