Electromagnetic pulses generated in high-power laser–solid interactions can cause serious electromagnetic interference and threaten diagnostic systems, making their mechanism study essential.

This work aims to investigate the characteristics and generation mechanisms of electromagnetic pulses induced by picosecond and nanosecond laser irradiation on solid targets.

Experiments were carried out on the Shenguang II upgrade laser facility. The temporal waveforms and frequency spectra of the emitted electromagnetic fields were measured under various pulse durations, laser energies, and irradiation geometries.

For picosecond laser irradiation, the electromagnetic pulses mainly originated from the neutralization current flowing through the target mount, and the peak electric field increased nearly linearly with laser energy. In the nanosecond experiments, the electromagnetic pulse intensity was lower, with the electric field oscillation decaying rapidly and a quasi-DC component observed. Using only the upper eight nanosecond beams produced stronger pulses than sixteen-beam irradiation, showing a modulation. In the combined picosecond and nanosecond laser experiment, the electromagnetic pulse peak generated by the picosecond laser was significantly reduced, which is attributed to the large-scale plasma formed by the nanosecond laser.

These findings clarify the generation behavior of electromagnetic pulses and provide references for mitigating electromagnetic interference in high-power laser experiments.