Underdense metal targets for laser-plasma experiments

Through theoretical analysis and numerical simulations, we investigated the process of femtosecond-intense-laser-driven wake-field acceleration in underdense plasmas composed of different metals. Based on the wake-field acceleration mechanism, we propose that the yield of betatron photons in metallic plasmas can be further enhanced compared to that in non-metallic plasmas. To simplify the problem, we modeled low-ionization plasmas with varying expansion distances as idealized approximations of real experimental conditions. We investigated the effects of parameters such as density gradient, plasma region thickness, and plasma density on the properties of electron beams and emitted X-rays. Finally, we introduced a method for generating underdense metal plasma. In practical laser-plasma experiments, the three-dimensional position of the target must be adjustable with micrometer precision. Accordingly, we proposed a specific design for underdense metal targets. Our research may provide guidance for further studies on the interaction between lasers and underdense metal plasmas.