Channeling of intense laser beams in underdense plasmas

A hydrodynamic simulation is used to show that intense laser pulses propagating in underdense plasmas create stable, long-lived, and completely evacuated channels. At low intensities, ${I=10\mathrm{}}^{17}$ ${\mathrm{W}/\mathrm{c}\mathrm{m}}^2,$ self focusing seriously distorts the temporal envelope of the pulse, but channeling still occurs. At high intensities, ${I=10\mathrm{}}^{19}$ ${\mathrm{W}/\mathrm{c}\mathrm{m}}^2,$ channeling can proceed over many diffraction lengths with significant distortion restricted to the leading edge of the pulse.