Water-Window Soft X-Ray Spectra from Dual Laser-Produced Bi Plasmas

We described the spectral behavior of the water-window soft x-ray emission in detail by dual laser pulse irradiation. We also observed the spatial separation of the soft x-ray emission and fast ions produced using dual pulse irradiation. Soft x-ray emission distribution was almost isotropic, and the fast ions were emitted to the target normal along the pre-pulse laser axis. The soft x-ray emission was maximized at a delay time of 50 ns between the pre-pulse, and the main laser heating pulse when the pre-plasma was irradiated at a distance of 50 µm above the target.