@article{5727,
  author = {N. E. Andreev and V. I. Kirsanov and A. S. Sakharov and P. W. van Amersfoort and V. V. Goloviznin},
  title = {On the phase velocity of plasma waves in a self-modulated laser wake-field accelerator},
  abstract = {The properties of the wake field excited by a flattop laser pulse with a sharp leading edge and a power below the critical one for relativistic self-focusing are studied analytically and numerically with emphasis on the phase velocity of the plasma wave. The paraxial model describing modulation of the pulse spot size is shown to provide a good quantitative description, including preexponential factors, of the wake field during the linear stage of the resonant self-modulation instability. Though the phase velocity of the excited plasma wave is shown to be close to the group velocity of the laser pulse, the relativistic gamma-factor corresponding to the phase velocity, which is a crucial parameter for particle acceleration, can be substantially less than that of the group velocity. Fortunately, for the considered three-dimensional regime of self-modulation, the noticeable difference between these two gamma-factors takes place only in the initial stage of the instability and vanishes in the later stages. (C) 1996 American Institute of Physics.},
  year = {1996},
  journal = {Physics of Plasmas},
  volume = {3},
  number = {8},
  pages = {3121-3128},
  month = {Aug},
  isbn = {1070-664X},
  doi = {10.1063/1.871659},
  language = {eng},
}