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 dynam ics 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 insta ntaneous image of EPW was also obtained. The asymmetric 2D image was explai ned by the modified liner theory. These experimental results suggest that t he intensity of similar to 10(18) W/cm(2) was achieved in the low density s tatic gas target. This means the possibility of not only the coherent contr ol of EPW, but also the long relativistic and charge-displacement self-chan neling 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.