Weak delocalization of a high-power single laser beam propagating through a low-density plasma compared to stable propagation in vacuum. Here we see time-resolved 2D beam spatial distributions of a single beam propagating through a 0.008nc plasma. The delocalization is much weaker than at higher density. 0 ps indicates the temporal peak of the pulse. Each 2D transverse beam image is integrated over 30 ps and is rescaled in brightness to the maximum intensity within the image. The laser pulse has an energy ~20 J (wavelength 1.05 micron, duration 400 ps FWHM, horizontal polarization). It was focused at a maximum intensity of 3*10^14 W.cm^-2 in the centre of a supersonic Helium jet with a 1mm diameter opening.
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