Diagnosing fuel areal density asymmetries in deuterium-tritium inertial

Raspberry Simpson


Tuesday, November 20, 2018



PSFC Student Seminars

In deuterium-tritium (DT) inertial confinement fusion implosions, one of the major challenges of ICF is to maintain a symmetric implosion and it is speculated that removing these asymmetries could improve the likelihood of fusion ignition. An important figure of merit in ICF is the fuel areal density (ρR), which describes the amount of compression achieved and thus the amount of confinement. Therefore, it is crucially important to be able to measure ρR and variations of ρR in order to diagnose implosion asymmetries. On the OMEGA facility, two Charged Particle Spectrometers (CPS’s) have been used to infer fuel ρR asymmetries in cryogenic deuterium-tritium implosions by measuring the spectrum of knock-on deuterons emitted in different directions. These knock-on deuterons are produced by elastic scattering between primary DT neutrons and deuterium fuel. The CPS’s, which are located along different lines-of-sight, provide a complimentary measurement to the neutron-based ρR measurements. In this work, we discuss the knock-on deuteron data obtained in the 1-D cryogenic DT Campaign at OMEGA. Preliminary data analysis reveals that there is a systematic asymmetry in the direction of one of the charged particle spectrometers of approximately 20%.