Observation of a hot high-current electron beam from a self-modulated laser wakefield accelerator

A highly relativistic electron beam produced by a 50 TW laser-plasma accelerator has been characterized by photonuclear techniques. The beam has large divergence that increases with plasma density. The electron yield also increases with plasma density and reaches up to 4 X 10(11) electrons (>10 MeV), with beam current approaching the Alfven limit. Effective electron temperatures exceeding 8 MeV are found, leading to an order of magnitude higher photonuclear activation yield than in solid target experiments with the same laser system.