D-He Proton Spectra for Diagnosing Shell ρR and Fuel Ti of Imploded Capsules at OMEGA

Recent work has resulted in the first high-resolution, spectroscopic measurements of energetic charged particles on OMEGA. Energy spectra of charged fusion products have been obtained from two spectrometers, and have been used to deduce various physical quantities in imploded capsules. In this paper we discuss the first use of 14.7-MeV D-He proton spectra for diagnosing shell areal density (ρR) and fuel ion temperature (Ti). For thick-plastic shell capsules, shell areal densities between 20 and 70 mg/cm and ion temperatures between 3 and 5 keV have been determined. The spectral line widths associated with such capsules are found to be clearly wider than the doppler widths. This effect, the focus of future study, is possibly the result of ρR evolution during the burn; or is the result of an extended burn region; or results from nonuniformities in the shell. For thin-glass shell capsules, the spectral line widths are dominated by the doppler width, and ion temperatures between 10 and 15 keV were determined. We also compare and contrast these measurements with the results from neutron measurements and from 1-D hydrodynamic simulations. PACS numbers: 52.70.Nc, 52.40.Nk, 52.58.Ns, 52.55.Pi * Also Visiting Senior Scientist at LLE. = Presently at Questra Consulting. == Presently at Xenogen .