A tabletop accelerator——the laser wakefield accelerator

With the development of chirped pulse technology in recent years significant progress has also been achieved in laser wakefield accelerators. Compared with traditional rf-cavity schemes its acceleration gradient r is three orders of magnitude larger, as high as 100GeV/m. Under such conditions electrons can be accelerated to over 1GeV within 1cm. We present an overview of this new scheme, concentrating on the wakefield generation, electron injection and increase of the acceleration distance.