Diagnosis of High-Temperature Implosions Using Low- and High-Opacity Krypton Lines

Article type: Research Article

Authors: Yaakobi, B. | Epstein, R. | Hooper Jr., C. F. | Haynes Jr., D. A. | Su, Q.

Affiliations: Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 | Department of Physics, University of Florida, Gainesville, Florida 32611 | Department of Physics, Illinois State University, Normal, Illinois 61790-4560

Abstract: High-temperature laser target implosions can be achieved by using relatively thin-shell targets, and they can be diagnosed by doping the fuel with krypton and measuring K-shell and L-shell lines. Electron temperatures of up to 5 keV at modest compressed densities (~ 1–5 g/cm3) are predicted for such experiments, with ion temperatures peaking above 10 keV at the center. It is found that the profiles of low-opacity (optically thin) lines in the expected density range are dominated by the Doppler broadening and can provide a measurement of the ion temperature if spectrometers of spectral resolution Δλ/λ ≥ 1000 are used. For high-opacity lines, obtained with a higher krypton fill pressure, the measurement of the escape factor can yield the ρR of the compressed fuel. At higher densities, Stark broadening of low-opacity lines becomes important and can provide a density measurement, whereas lines of higher opacity can be used to estimate the extent of mixing.

DOI: 10.3233/XST-1996-6205

Journal: Journal of X-Ray Science and Technology, vol. 6, no. 2, pp. 172-187, 1996