Prospects for fluorescence based imaging/visualization of hydrodynamic systems on the National Ignition Facility

The next generation of large, high power lasers, such as the National Ignit ion Facility in the U.S., Laser Mega Joule in France or Helen Successor in the United Kingdom offers the prospect of x-ray fluorescence based diagnosi s of hydrodynamic experiments. We discuss two promising techniques for pump ing this fluorescence. One is to use a large fraction of these facilities' high power to efficiently make multi-kilovolt x rays which, in turn, causes dopants placed in experimental packages to fluoresce. The second technique is to use the sizable multi-kilovolt photon background that we expect to b e present in many hohlraum based experiments, while the driving laser is on , to pump x-ray fluorescence. Here, the fluorescing medium could be a dopan t in an experimental package or, possibly, a relatively thick slab of mater ial in the hohlraum wall which could serve as a backlighter. (C) 1999 Ameri can Institute of Physics. [S0034-6748(99)63301-9].