Laser wakefield in low density plasma

The laser wakefiled (LWF) and the relativistic and charge-displacement self-channeling in the comparatively low density plasma were studied. The dynamics of the electron plasma wave (EPW) in LWF was experimentally observed at the electron density of similar to 10(16) cm(-3) The two dimensional instantaneous image of EPW was also obtained. The asymmetric 2D image was explained by the modified liner theory. These experimental results suggest that the intensity of similar to 10(18) W/cm(2) was achieved in the low density static gas target. This means the possibility of not only the coherent control of EPW, but also the long relativistic and charge-displacement self-channeling with the low density static gas. For the self-channeling, the simple model tells us that the long channel without defocusing could be possible with a tens of TW; ps glass laser system.