Shock-tuned cryogenic-deuterium-tritium implosion performance on Omega

• Published in: Physics of plasmas 2010-05, Vol.17 (5)
• Main Authors: Sangster, T. C., Goncharov, V. N., Betti, R., Boehly, T. R., Casey, D. T., Collins, T. J. B., Craxton, R. S., Delettrez, J. A., Edgell, D. H., Epstein, R., Fletcher, K. A., Frenje, J. A., Glebov, Y. Yu, Harding, D. R., Hu, S. X., Igumenschev, I. V., Knauer, J. P., Loucks, S. J., Li, C. K., Marozas, J. A., Marshall, F. J., McCrory, R. L., McKenty, P. W., Meyerhofer, D. D., Nilson, P. M., Padalino, S. P., Petrasso, R. D., Radha, P. B., Regan, S. P., Seguin, F. H., Seka, W., Short, R. W., Shvarts, D., Skupsky, S., Smalyuk, V. A., Soures, J. M., Stoeckl, C., Theobald, W., Yaakobi, B.
• Format: Article
• Language: English
• Subjects: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; BETA DECAY RADIOISOTOPES; BETA-MINUS DECAY RADIOISOTOPES; CONFINEMENT; DEUTERIUM; HYDROGEN ISOTOPES; IMPLOSIONS; INERTIAL CONFINEMENT; ION TEMPERATURE; ISOTOPES; LASER IMPLOSIONS; LASERS; LIGHT NUCLEI; NUCLEI; ODD-EVEN NUCLEI; ODD-ODD NUCLEI; PLASMA CONFINEMENT; PLASMA DIAGNOSTICS; RADIOISOTOPES; SHOCK WAVES; STABLE ISOTOPES; TRITIUM; YEARS LIVING RADIOISOTOPES
• ISSN: 1070-664X; 1089-7674
• DOI: 10.1063/1.3360928

Cryogenic-deuterium-tritium (DT) target compression experiments with low-adiabat (α), multiple-shock drive pulses have been performed on the Omega Laser Facility [T. R. Boehly, D. L. Brown, R. S. Craxton et al., Opt. Commun. 133, 495 (1997)] to demonstrate hydrodynamic-equivalent ignition performance. The multiple-shock drive pulse facilitates experimental shock tuning using an established cone-in-shell target platform [T. R. Boehly, R. Betti, T. R. Boehly et al., Phys. Plasmas 16, 056301 (2009)]. These shock-tuned drive pulses have been used to implode cryogenic-DT targets with peak implosion velocities of 3×107 cm/s at peak drive intensities of 8×1014 W/cm2. During a recent series of α∼2 implosions, one of the two necessary conditions for initiating a thermonuclear burn wave in a DT plasma was achieved: an areal density of approximately 300 mg/cm2 was inferred using the magnetic recoil spectrometer [J. A. Frenje, C. K. Li, F. H. Séguin et al., Phys. Plasmas 16, 042704 (2009)]. The other condition—a burn-averaged ion temperature ⟨Ti⟩n of 8–10 keV—cannot be achieved on Omega because of the limited laser energy; the kinetic energy of the imploding shell is insufficient to heat the plasma to these temperatures. A ⟨Ti⟩n of approximately 3.4 keV would be required to demonstrate ignition hydrodynamic equivalence [Betti et al., Phys. Plasmas17, 058102 (2010)]. The ⟨Ti⟩n reached during the recent series of α∼2 implosions was approximately 2 keV, limited primarily by laser-drive and target nonuniformities. Work is underway to improve drive and target symmetry for future experiments.