Strong terawatt pulses for the efficient plasma-based x-rays generation in flat water jet

By using subpicosecond terawatt infrared pulses, we demonstrate strong x-rays generation in flat water jet. Varying the pump energy, pulse duration and its chirp along with measuring the angular x-ray distribution, we define the conditions which allow achieving the most intense x-ray emission. The terawatt powers made it possible to reveal two characteristic regimes of x-ray pulse energy dependence, namely, quasi-quadratic growth and the following saturation. The strong asymmetry of the x-ray yield dependences on the pump pulse duration for various chirp signs and the positive chirp preference correspond to the earlier studies and are mainly determined by the change in the electron temperature. Theoretical analysis of ionized electrons density dynamics reveals strong correlation with x-rays experimental data. We believe, our findings can be a promising basis for further development of highly intense femtosecond x-ray generators based on the metallic soluble substances.