Search Menu
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information
Search Scholarly Publications

13 Search Results

Sorted by Relevance
Save Results
...

  1. X-Ray Thomson-Scattering Measurements of Density and Temperature in Shock-Compressed Beryllium

    Lee, H. J. ; Neumayer, P. ; Castor, J. ; ... - Physical Review Letters
    We present the first x-ray scattering measurements of the state of compression and heating in laser irradiated solid beryllium. The scattered spectra at two different angles show Compton and plasmon features indicating a dense Fermi-degenerate plasma state with a Fermi energy above 30 eV and with temperatures in the range of 10 eV to 15 eV. These measurements indicate compression by a factor of three in agreement with Hugoniot data and detailed radiation hydrodynamic modeling.

  2. Properties of the electron cloud in a high-energy positron and electron storage ring

    Harkay, K. C. ; Rosenberg, R. A. - Physical Review Special Topics. Accelerators and Beams
    Low-energy, background electrons are ubiquitous in high-energy particle accelerators. Under certain conditions, interactions between this electron cloud and the high-energy beam can give rise to numerous effects that can seriously degrade the accelerator performance. These effects range from vacuum degradation to collective beam instabilities and emittance blowup. Although electron-cloud effects were first observed two decades ago in a few proton storage rings, they have in recent years been widely observed and intensely studied in positron and proton rings. Electron-cloud diagnostics developed at the Advanced Photon Source enabled for the first time detailed, direct characterization of the electron-cloud properties in amore » positron and electron storage ring. From in situ measurements of the electron flux and energy distribution at the vacuum chamber wall, electron-cloud production mechanisms and details of the beam-cloud interaction can be inferred. A significant longitudinal variation of the electron cloud is also observed, due primarily to geometrical details of the vacuum chamber. Furthermore, such experimental data can be used to provide realistic limits on key input parameters in modeling efforts, leading ultimately to greater confidence in predicting electron-cloud effects in future accelerators.« less

  3. Steady-state planar ablative flow

    Manheimer, W. M. ; Colombant, D. G. ; Gardner, J. H. - Physics of Fluids (New York)
    Steady-state planar ablative flow in a laser produced plasma is studied. The calculations relate all steady-state fluid quantities to only three parameters, the material, absorbed irradiance, and laser wavelength. Here, the fluid is divided into three regions; the subcritical expanding plasma, the steady-state ablation front, and the accelerated slab. Boundary conditions at the interfaces of these regions are given. If the absorbed irradiance is nonuniform, the nonuniformity in ablation pressure is calculated. Results are compared with experiment and fluid simulation for both uniform and nonuniform illumination.
...
Search for:
All Records
Subject
SIMULATION
Refine by:
Article Type
Availability
Journal
more less
Creator / Author
more less
Publication Date
Research Organization
more less