[摘要]：Self-formed plasma channels induced by ultra-intense and ultra-short laser pulses have been investigated with 2.5-dimensional particle-in-cell simulations. A criterion of channel formation under the highly relativistic regime is proposed and tested by simulation results. Good matches between criterion predictions and simulations are found in most cases, but small deviations occur when the plasma density is very low or near critical. The possibility of generating a channel by a femtosecond pulsed laser is also discussed. (C) 2011 American Institute of Physics. [doi:10.1063/1.3665181]
