Charged-Particle Spectroscopy of Inertial Fusion Implosions

Alex Zylstra, Massachusetts Institute of Technology

Charged-particle spectroscopy as a diagnostic of inertial fusion implosions has been well established at the Omega facility over the past decade. In recent work we have fielded compact proton spectrometers on the National Ignition Facility as an ignition campaign diagnostic. In tuning campaign implosions containing D and helium-3 gas, the WRFs are used to measure the spectrum of protons from D-3He reactions. From the measured energy downshift of the D-3He protons, the total ρR is inferred through the plasma stopping power. Data from WRFs fielded simultaneously on the pole and equator indicate low-mode polar ρR asymmetries at shock flash. Significant swings in ρR P2/P0 are also observed over the ignition campaign data set, attributed to low-mode X-ray drive inhomogeneity. In addition, we report on new applications of charged-particle spectroscopy to studies of astrophysically relevant nuclear reactions using ICF plasmas, in particular the reaction 3He+3He, which is the dominant energy-producing reaction in low-mass hydrogen-burning stars like our sun.

Abstract Author(s): A.B. Zylstra et al.