High-density carbon ablator experiments on the National Ignition Facility

A. J. MacKinnon*, N. B. Meezan, J. S. Ross, S. Le Pape, L. Berzak Hopkins, L. Divol, D. Ho, J. Milovich, A. Pak, J. Ralph, T. Doeppner, P. K. Patel, C. Thomas, R. Tommasini, S. Haan, A. G. MacPhee, J. McNaney, J. Caggiano, R. Hatarik, R. BiontaT. Ma, B. Spears, J. R. Rygg, L. R. Benedetti, R. P. J. Town, D. K. Bradley, E. L. Dewald, D. Fittinghoff, O. S. Jones, H. R. Robey, J. D. Moody, S. Khan, D. A. Callahan, A. Hamza, J. Biener, P. M. Celliers, D. G. Braun, D. J. Erskine, S. T. Prisbrey, R. J. Wallace, B. Kozioziemski, R. Dylla-Spears, J. Sater, G. Collins, E. Storm, W. Hsing, O. Landen, J. L. Atherton, J. D. Lindl, M. J. Edwards, J. A. Frenje, M. Gatu-Johnson, C. K. Li, R. Petrasso, H. Rinderknecht, M. Rosenberg, F. H. Seguin, A. Zylstra, J. P. Knauer, G. Grim, N. Guler, F. Merrill, R. Olson, G. A. Kyrala, J. D. Kilkenny, A. Nikroo, K. Moreno, D. E. Hoover, C. Wild, E. Werner

*Corresponding author for this work

Research output: Contribution to journalArticle

90 Citations (Scopus)

Abstract

High Density Carbon (HDC) is a leading candidate as an ablator material for Inertial Confinement Fusion (ICF) capsules in x-ray (indirect) drive implosions. HDC has a higher density (3.5 g/cc) than plastic (CH, 1 g/cc), which results in a thinner ablator with a larger inner radius for a given capsule scale. This leads to higher x-ray absorption and shorter laser pulses compared to equivalent CH designs. This paper will describe a series of experiments carried out to examine the feasibility of using HDC as an ablator using both gas filled hohlraums and lower density, near vacuum hohlraums. These experiments have shown that deuterium (DD) and deuterium-tritium gas filled HDC capsules driven by a hohlraum filled with 1.2 mg/cc He gas, produce neutron yields a factor of 2x higher than equivalent CH implosions, representing better than 50% Yield-over-Clean (YoC). In a near vacuum hohlraum (He = 0.03 mg/cc) with 98% laser-to-hohlraum coupling, such a DD gas-filled capsule performed near 1D expectations. A cryogenic layered implosion version was consistent with a fuel velocity = 410 +/- 20 km/s with no observed ablator mixing into the hot spot. (C) 2014 AIP Publishing LLC.

Original languageEnglish
Article number056318
Number of pages11
JournalPhysics of Plasmas
Volume21
Issue number5
DOIs
Publication statusPublished - May 2014

Keywords

  • indirect-drive targets
  • laser

Cite this

MacKinnon, A. J., Meezan, N. B., Ross, J. S., Le Pape, S., Hopkins, L. B., Divol, L., Ho, D., Milovich, J., Pak, A., Ralph, J., Doeppner, T., Patel, P. K., Thomas, C., Tommasini, R., Haan, S., MacPhee, A. G., McNaney, J., Caggiano, J., Hatarik, R., ... Werner, E. (2014). High-density carbon ablator experiments on the National Ignition Facility. Physics of Plasmas, 21(5), [056318]. https://doi.org/10.1063/1.4876611