Showing papers by "R. A. Snavely published in 1999"
TL;DR: The Petawatt laser at LLNL has opened a new regime of laser-matter interactions in which the quiver motion of plasma electrons is fully relativistic with energies extending well above the threshold for nuclear processes as discussed by the authors.
Abstract: The Petawatt laser at LLNL has opened a new regime of laser-matter interactions in which the quiver motion of plasma electrons is fully relativistic with energies extending well above the threshold for nuclear processes. In addition to -few MeV ponderomotive electrons produced in ultra-intense laser-solid interactions, we have found a high energy component of electrons extending to -100 MeV apparently from relativistic self-focusing and plasma acceleration in the underdense pre-formed plasma. The generation of hard bremsstrahlung, photo-nuclear reactions, and preliminary evidence for positron-electron pair production will be discussed.
135 citations
TL;DR: In this article, a series of experiments using the Petawatt laser system at LLNL were conducted to determine the potential of hard x-ray sources for radiography applications and the physics of these sources and the scaling relationships and laser technology required to provide the dose levels necessary for radiograph applications were discussed.
Abstract: Intense laser (>1021 W/cm2) driven hard x-ray sources offer a new alternative to conventional electron accelerator bremsstrahlung sources. These laser driven sources offer considerable simplicity in design and cost advantage for multiple axis views and have the potential for much higher spatial and temporal resolution than is achievable with accelerator sources. We have begun a series of experiments using the Petawatt laser system at LLNL to determine the potential of these sources for radiography applications. Absolutely calibrated spectra extending to 20 MeV and high resolution radiographs through a ρr⩾150 g/cm2 have been obtained. The physics of these sources and the scaling relationships and laser technology required to provide the dose levels necessary for radiography applications will be discussed. Diagnostics of the laser produced electrons and photons will be addressed.
91 citations