摘要
The optical guiding of a moderately intense laser pulse in a parabolic preformed plasma channel is analyzed by means of the variational method.Relativistic,ponderomotive and their coupling nonlinearities are included.The conditions for periodic defocusing and focusing,as well as constant spot size propagation are given.It is found that the laser focusing is released by the coupling of relativistic and ponderomotive nonlinearities.
基金
Supported by the National Natural Science Foundation of China under Grant Nos. 11047152,11147005,and 11178002
the Natural Science Foundation of Jiangxi Province under Grant No. 2010GQW0048