Imaging of High-Energy X-Ray Emission from Cryogenic Thermonuclear Fuel Implosions on the NIF

Conference · Tue May 01 04:00:00 EDT 2012

DOI:https://doi.org/10.1063/1.4733313· OSTI ID:1043646

Ma, T

Accurately assessing and optimizing the implosion performance of inertial confinement fusion capsules is a crucial step to achieving ignition on the NIF. We have applied differential filtering (matched Ross filter pairs) to provide spectrally resolved time-integrated absolute x-ray self-emission images of the imploded core of cryogenic layered targets. Using bremsstrahlung assumptions, the measured absolute x-ray brightness allows for the inference of electron temperature, electron density, hot spot mass, mix mass, and pressure. Current inertial confinement fusion (ICF) experiments conducted on the National Ignition Facility (NIF) seek to indirectly drive a spherical implosion, compressing and igniting a deuterium-tritium fuel. This DT fuel capsule is cryogenically prepared as a solid ice layer surrounded by a low-Z ablator material. Ignition will occur when the hot spot approaches sufficient temperature ({approx}3-4 keV) and {rho}R ({approx}0.3 g/cm{sup 2}) such that alpha deposition can further heat the hot spot and generate a self-sustaining burn wave. During the implosion, the fuel mass becomes hot enough to emit large amounts of x-ray radiation, the spectra and spatial variation of which contains key information that can be used to evaluate the implosion performance. The Ross filter diagnostic employs differential filtering to provide spectrally resolved, time-integrated, absolute x-ray self-emission images of the imploded core of cryogenic layered targets.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA
• Sponsoring Organization: USDOE
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 1043646
• Report Number(s): LLNL-CONF-555311
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BREMSSTRAHLUNG
BRIGHTNESS
CRYOGENICS
DEPOSITION
ELECTRON DENSITY
ELECTRON TEMPERATURE
HOT SPOTS
IGNITION
IMPLOSIONS
INERTIAL CONFINEMENT
PERFORMANCE
PLASMA DIAGNOSTICS
SPECTRA
TARGETS
THERMONUCLEAR FUELS
US NATIONAL IGNITION FACILITY