Numerical Simulation of the SGEMP Inside a Target Chamber of a Laser Inertial Confinement Facility

After X-ray irradiate a metal cavity, a large number of photoelectrons are emitted into the internal space, thereby producing a very strong system-generated electromagnetic pulse (SGEMP). The X-ray environment inside a laser inertial confinement device is very complex. Even if the diagnostic equipment working inside the target chamber has a good electromagnetic shielding capability, it would still face severe SGEMP interference. In this paper, the X-ray environments inside target chambers of National Ignition Facility, optimized method for estimated guidance accuracy (OMEGA), and Shenguang-III (SG-III) facility were obtained through a survey of the literature. In light of the survey results, the time-biased finite-difference time-domain method and the particle-in-cell method were used to numerically simulate SGEMP inside a 2-D cylindrical cavity model. Besides, the relationships between the SGEMP in the cavity and parameters such as X-ray fluence, energy spectrum, pulsewidth, and spatial size of the model were studied. The fluence and pulsewidth of the X-ray were found to have a more significant effect on the time-domain waveform of the electromagnetic field. Finally, based on the calculation results, the SGEMP of the SG-III facility in the target chamber was calculated to approximately be 0.75 MV/m.