68 / 2023-04-12 13:24:06

Three-dimensional iterative reconstruction of pulsed radiation sources using cylindrical harmonic decomposition and deep image prior post-processing

three-dimensional reconstruction,cylindrical harmonic decomposition,deep image prior,Z-pinch

The spatial structure diagnosis of the burning plasma during the ignition stage of inertial confinement fusion implosion is important for evaluating the ignition state, verifying physical models and improving experimental parameters. Multiaxial passive imaging is generally used to acquire three-dimensional (3D) information of pulsed radiation sources. Only a small number of two-dimensional (2D) line-integral projection images obtained along several imaging axes are available due to the short durations of pulsed sources and the limitations of current technology. The reconstruction of a 3D source with a minimal number of 2D images is an ill-posed problem that leads to severe artifacts in the image reconstructed by conventional algorithms. In this paper, we propose an iterative image reconstruction method using cylindrical harmonic decomposition and a deep learning post-processing method based on deep image prior. We get high-quality reconstruction results and obtain the three-dimensional intensity distribution and evolution of extreme ultraviolet and soft X-ray emitted by plasma with the single-wire Z-pinch imaging data at three angles and four moments. The reconstruction results show that the plasma did not undergo uniform confinement, and the structure of sausage instability first appeared, followed by a significant distortion of kink instability.