Improvement of the accuracy in measuring cryogenic hot spot mix by multi-channel Ross filter pairs through a two-temperature model of hot spot electron temperature

Rev Sci Instrum. 2025 Jan 1;96(1):013505. doi: 10.1063/5.0220582.

Abstract

In inertial confinement fusion experiments, hot spot mix caused by hydrodynamic instabilities is a critical performance limitation. Currently, multi-channel Ross filter pair imaging is used to quantitatively diagnose the mix mass of cryogenic hot spots driven by 100 kJ energy, but this method brings significant uncertainty. To measure the level of mix more accurately, we have developed a two-temperature model to modify the fitted bremsstrahlung spectra based on the characteristics of cryogenic implosion hot spots. In experiments with good symmetry of hot spots, fitting analysis of the radial distribution of electron temperature was conducted. Compared with traditional single-temperature models, the two-temperature modeling method is more sensitive to the radial distribution of electron temperature and provides new diagnostic insights into the spatial distribution of cryogenic hot spot mix.