Measurement of Spatial Temperature, Density and Mix Distributions in Igniting Plasmas on the NIF

Now that NIF has achieved ignition and multiple experiments have achieved megajoule yields, we can study detailed plasma conditions in igniting plasmas. By combining multi-view, spectrally resolved x-ray [1] and neutron [2] imaging systems, we reconstruct time-integrated density and temperature profiles of burning hotspots near ignition. The differentially filtered x-ray imaging system constrains the electron temperature which, combined with neutron imaging, constrains the ion density without assuming that the system is isobaric [3]. With an absolutely calibrated x-ray measurement, we can extract the profile of ablator mix into the thermonuclear fuel. We can distinguish between localized mix (visible mix jets) and non-localized mix and quantify the corresponding mix mass and mix density.

[1] K. W. Wong and B. Bachmann, Rev. Sci. Instrum. 93, 073501 (2022)

[2] P. Volegov et al., J. Appl. Phys. 118, 205903 (2015)

[3] A. Pak et al., Phys. Rev. Lett. 124, 145001 (2020)