Theoretical studies on propagation of electromagnetic wave in preformed narrowed plasma channel

A cylindrical plasma waveguide, taking no account of the effect of collisions in the plasma, is derived to describe narrow channel generated by ultraintense laser pulse. Theory analysis shows that TE
_0m
and TM
_0m
and hybrid modes can be emerged in plasma waveguide, but they are also different from the conventional dielectric waveguide. The propagation of waveguide modes near cutoff and far from cutoff are considered, which is influenced by is the normalized frequency parameter B and numerical aperture NA.