Spatial and temporal evolution of electromagnetic pulses from solid target irradiated with multi-hundred-terawatt laser pulse inside target chamber

Giant electromagnetic pulses (EMPs) induced by high-power laser irradiating solid targets interfere with various experimental diagnoses and even damage equipment, so unveiling the evolution of EMPs inside the laser chamber is crucial for designing effective EMP shielding. In this work, the transmission characteristics of EMPs as a function of distances from the target chamber center (TCC) are studied using B-dot probes. The mean EMP amplitude generated by picosecond laser-target interaction reaches 561 kV m⁻¹, 357 kV m⁻¹, 395 kV m⁻¹, and 341 kV m⁻¹ at 0.32 m, 0.53 m, 0.76 m, and 1 m from TCC, which decreases dramatically from 0.32 m to 0.53 m. However, it shows a fluctuation from 0.53 m to 1 m. The temporal features of EMPs indicate that time-domain EMP signals near the target chamber wall have a wider full width at half maximum compared to that close to TCC, mainly due to the echo oscillation of electromagnetic waves inside the target chamber based on simulation and experimentation. The conclusions of this study will provide a new approach to mitigate strong electromagnetic pulses by decreasing the echo oscillation of electromagnetic waves inside the target chamber during laser coupling with targets.