High-repetition-rate source of nanosecond duration kA-current pulses driven by relativistic laser pulses

14 marzo 2024

We report the first high-repetition rate generation and simultaneous characterization of nanosecond-scale return currents of kA-magnitude issued by the polarization of a target irradiated with a PW-class high-repetition-rate Ti: Sa laser system at relativistic intensities. We present experimental results obtained with the VEGA-3 laser at intensities from 5 × 1018 W cm-2 to 1.3 × 1020 W cm-2. A non-invasive inductive return-current monitor is adopted to measure the derivative of return-currents on the order of kA ns−1 and analysis methodology is developed to derive return-currents. We compare the current for copper, aluminum, and Kapton targets at different laser energies. The data shows the stable production of current peaks and clear prospects for the tailoring of the pulse shape, promising for future applications in high energy density science, e.g. electromagnetic interference stress tests, high-voltage pulse response measurements, and charged particle beam lensing. We compare the target discharge of the order of hundreds of nC with theoretical predictions and a good agreement is found.