LLE Review 154

Review 154


This volume of the LLE Review, covering January–March 2018, features "Analysis of Trends in Implosion Observables for Direct-Drive Cryogenic Implosions on OMEGA," which describes a technique to identify trends in performance degradation for inertial confinement fusion implosion experiments. It is based on reconstruction of the implosion core with a combination of low- and mid-mode asymmetries.

Additional highlights of research presented in this issue include the following:

  • The successful use of the flying focus technique that uses a chirped laser beam focused by a highly chromatic lens to produce an extended focal region to measure sub- and superluminal ionization fronts that propagated forward and backward relative to the ionizing laser is demonstrated.
  • A new single-line-of-sight, time-resolved x-ray imager diagnostic for OMEGA that measures the evolution of the stagnation core was developed. The diagnostic is mounted on a fixed port almost perpendicular to a 16-channel, framing-cameraŠbased, time-resolved Kirkpatrick–Baez microscope, providing a second time-gated line of sight for hot-spot imaging on OMEGA.
  • The activation of a supersonic gas-jet target platform on the OMEGA laser is discussed. Initial measurements demonstrate the capabilities of the OMEGA gas jet as a platform for future laserŠplasma interaction science.
  • The study of scaling using laser-driven magnetized liner inertial fusion (MagLIF) on OMEGA is discussed. It is proposed that full laser energy transmission is achieved by relativistic self-focusing, enhanced by focusing related to the electron density profile that forms, followed by a ponderomotive blowout of the plasma.
  • The use of a Wollaston interferometer to measure the density of plasma plumes created in experiments on the OMEGA EP Laser System is presented. The unique advantages of this system over standard interferometric means are discussed.
  • A demonstration of how x-ray imaging using shaped crystals in Bragg reflection is a powerful technique used in high-energy-density physics experiments is given. The 10-J, 1-ps Multi-Terawatt (MTW) laser was used to characterize a set of Bragg crystal assemblies.
  • The development of a new neutron time-of-flight diagnostic with an ultrafast instrument response function that has been fielded on the OMEGA laser in a highly collimated line of sight is presented. The fast instrument response enables the accurate measurement of primary DT neutron peak shape while the optical fiducial allows for an absolute neutron energy measurement.

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