In the laser plasma interaction of quantum electrodynamics (QED) dominated regime, γ-rays are generated due to synchrotron radiation from high-energy electrons traveling in a strong, background electromagnetic field. With the aid of 2D particle-in-cell code including QED physics, we investigate the pre-plasma effect on the γ-rays generation during the interaction between an ultraintense laser pulse and solid targets. We found that with the increasing of the preplasma scale length, the γ-rays emission is enhanced significantly and finally comes to a steady state. Meanwhile, the γ-rays beam become collimated. It shows that in some cases the preplasmas will be piled up acting as a plasma mirror in the underdense preplasma region, where the γ-rays are produced by the collision between the forward electrons and the reflected laser fields from the piled plasma. The piled plasma plays the same role as usual reflection mirror making from solid target. Thus single solid target with proper scale length preplasma can serve as manufactural and robust gamma-ray source.
Wang Xiang-bing, Hu Guangyue, Zhang Zhi-meng, Gu Yuqiu, Zhao Bin, Zuo Yang, Zheng Jian. Gamma-ray generation from ultraintense laser-irradiated solid targets with preplasma[J]. High Power Laser Science and Engineering, , (): .
