Numerical and experimental study on mitigation of electromagnetic pulses at XG-III laser facility

Laser-target interaction generates intense electromagnetic pulses (EMPs), which severely interfere physical diagnostics and even damage equipment. Since EMP generation is mainly attribute to electron emission and return current along the target holder, numerical simulations and experimental verification are combined to reveal the contributions of these two sources. The results indicate a conductive target holder radiates EMPs with a higher magnitude of 189.5 kV/m than 88.9 kV/m for an insulating one. A double-layer aluminum shielding cage can effectively reduce EMP from 314.21 kV/m to 58.46 kV/m. In contrast, polytetrafluoroethylene (PTFE) is hardly to withstand the EMP penetration. The simulations are well verified by experimental results. These findings are helpful to develop the effective strategies to mitigate EMPs at large laser infrastructure and ensure the safety of experimental setups.