Intense Electromagnetic Pulses Generated From kJ-Laser Interacting With Hohlraum Targets

Irradiating hohlraum targets with high-power laser pulses is a promising approach to achieve inertial confinement fusion (ICF). Unfortunately, such interaction is accompanied by intense electromagnetic pulses (EMPs). The EMPs can interfere with various physical diagnostic signals and even cause a malfunction of some crucial equipment. In this study, EMPs generated due to kJ-laser coupling with hohlraum targets are recorded using B-dot probes inside the target chamber. The configuration of the hohlraum has a more remarkable effect on EMP amplitudes compared to laser energy. 0.6 mg/cc of He gas filling in the hohlraum and the presence of the capsule inside the hohlraum both dramatically reduce EMPs. Moreover, EMP frequencies corresponding to various hohlraums are basically below 1.75 GHz. Soft X-ray (0.1–4 keV) radiant flux is used to reveal the characteristics of EMPs. The conclusions are expected to enable us to better understand the relationship of EMPs with target configuration and laser energy.