LLE Review 86

Review 86

Highlights

LLE Review 86, covering January-March 2001, features an article (cover and p. 47) on the characterization of direct-drive implosion core conditions using time-resolved Ar K-shell spectroscopy. Electron densities in excess of 2.5 × 1024 cm-3 and electron temperatures ~2.5 keV were measured in these experiments. This represents the highest combination of electron temperature and density measured for these types of implosions in laser-driven inertial fusion experiments.

Additional research reported in this volume:

  • Studies of the implosions of direct-drive, DT-gas-filled polymer capsules using nuclear diagnostics. A comprehensive array of traditional neutron measurements as well as charged-particle diagnostics were used to compare the performance of capsules irradiated with full beam smoothing versus implosions of similar targets carried out with reduced beam smoothing.
  • The development of a measurement-based static model of the stagnated core and fuel-pusher mix. Excellent agreement with a suite of neutron and charged-particle diagnostics is obtained through this model.
  • The implementation of a high-resolution neutron imaging system on OMEGA by scientists from the Commissariat à L'Énergie Atomique (CEA) of France, Los Alamos National Laboratory (LANL), and LLE. This system is based on penumbral imaging and has an ultimate spatial resolution of ~13 µm for OMEGA implosions.
  • An analysis of the beam-smoothing performance of ultrafast picket-fence pulses for direct-drive targets on the NIF.
  • A report on a test of the feasibility of using extended x-ray absorption fine structure (EXAFS) spectra to characterize the properties of shocked solid materials.
  • A theoretical model for analyzing crack-load micro-indentation data in tetragonal crystals with particular application to KDP.

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