PLASMA-AIDED RADIATION GUIDING IN A FREE-ELECTRON LASER

The introduction of a plasma in a free-electron laser (FEL) helps radi ation guiding via nonlinear refraction, At high-radiation power densit y, when oscillatory electron velocity is comparable to the electron th ermal velocity, the radiation pushes plasma radially out, forming a de pleted plasma duct and guiding the radiation. The radius of the self-t rapped laser is similar to c/omega(po), where omega(po) is the unpertu rbed plasma frequency and c is the velocity of light in vacuum.