川超绵阳VS乐山

The concept of “moving beam” in near field is proposed. It is found that the device of smoothing by spectral dispersion （SSD） can generate “moving beam” in the near field. The mechanism and the condition for generating “moving beam”， the motion characteristics of the “moving beam”， and the suppression of small-scale self focusing are analyzed theoretically. The numerical simulations agree with the theoretical analyses.