Thermal decoupling of deuterium and tritium during the ICF shock-convergence phase

• Published in: Physical review. E 2021-07, Vol.104
• Main Authors: Kabadi, N. V., Simpson, R., Adrian, P. J., Bose, A., Frenje, J. A., Gatu Johnson, M., Lahmann, B., Li, C. K., Parker, C. E., Petrasso, R. D., Seguin, F. H., Sutcliffe, G. D., Forrest, C., Fess, S., Yu Glebov, V., Janezic, R., Mannion, O. M., Rinderknecht, H. G., Rosenberg, M. J., Stoeckl, C., Kagan, G., Hoppe, M., Luo, R., Schoff, M., Shuldberg, C., Sio, H. W., Sanchez, J., Berzak Hopkins, L., Schlossberg, D., Hahn, K., Yeamans, C., Eriksson, J., Atzeni, S.
• Format: Article
• Language: English
• Subjects: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; direct drive; fusion products; high-energy-density plasmas; indirect drive; inertial confinement fusion; nuclear fusion; plasma thermodynamics; space and astrophysical plasma
• ISSN: 2470-0045; 2470-0053

We report that a series of thin glass-shell shock-driven DT gas-filled capsule implosions was conducted at the OMEGA laser facility. These experiments generate conditions relevant to the central plasma during the shock-convergence phase of ablatively driven inertial confinement fusion (ICF) implosions. The spectral temperatures inferred from the DTn and DDn spectra are most consistent with a two-ion-temperature plasma, where the initial apparent temperature ratio, $\frac{T_T}{T_P}$, is 1.5. This is an experimental confirmation of the long-standing conjecture that plasma shocks couple energy directly proportional to the species mass in multi-ion plasmas. The apparent temperature ratio trend with equilibration time matches expected thermal equilibration described by hydrodynamic theory. This indicates that deuterium and tritium ions have different energy distributions for the time period surrounding shock convergence in ignition-relevant ICF implosions.