Detailed investigation of the iterative analysis for inertial confinement fusion target characterization

The iterative algorithm based on optical path difference and ray deflection (IAORD) is investigated in detail, and an advanced version (AIAORD) is proposed to obtain the refractive indices of the shell and the ice layer of the inertial confinement fusion (ICF) target simultaneously. The concept of the fixed-point iteration is introduced in the advanced algorithm, and it is found that the right choice of the combination of the input values and the characteristic curves is the key to ensure convergence in the iteration. The test uncertainties of the index measurement are analyzed by simulations, and they show that the uncertainties of the refractive indices of the shell and ice layer are 9.94% and 1.20%, respectively. Characteristic curves of typical ICF targets are studied, from which we conclude that AIAORD is versatile and suitable for the applications with any two unknown target parameters to be solved.