Single-Cycle High-Intensity Electromagnetic Pulse Generation in the   Interaction of a Plasma Wakefield with Nonlinear Coherent Structures
  The interaction of coherent nonlinear structures (such as sub-cycle solitons, electron vortices and wake Langmuir waves) with a strong wake wave in a collisionless plasma can be exploited in order to produce ultra-short electromagnetic pulses. The electromagnetic field of a coherent nonlinear structure is partially reflected by the electron density modulations of the incident wake wave and a single-cycle high-intensity electromagnetic pulse is formed. Due to the Doppler effect the length of this pulse is much shorter than that of the coherent nonlinear structure. This process is illustrated with two-dimensional Particle-in-Cell simulations. The considered laser-plasma interaction regimes can be achieved in present day experiments and can be used for plasma diagnostics. 
S. S. Bulanov, T. Zh. Esirkepov, F. F. Kamenets, F. Pegoraro