THE SANDIA X-RAY LASER PROGRAM

Le laser au rayon X en train d'être développé aux Laboratoires Sandia utilise un rayonnement keV intense, produit par la compression cylindrique ("Z-pinch") d'une bouffée de gaz, pour obtenir les ions de la série isoélectronique F par la photoionisation des ions Ne. Les populations des niveaux de la configuration (2p)5(3p) et de la configuration (2p)5(3s) sont inverties par des processus de recombinaison des ions. Une enveloppe annulaire de stagnation maintient la séparation entre la source du rayonnement et le plasma étant lasé. Une couche mince d'aluminium ou sodium sert pour changer la longueur d'onde du rayonnement. La méthode pour arriver aux dimensions et à la densité du laser au rayon X est décrite.The Sandia X-ray Laser Program is based on the use of intense keV radiation produced by gas puff, Z-pinch implosions to photoionize Ne-like ions to F-like ions. A 3p-3s population inversion is generated via recombination processes. An annular stagnation shell is used to separate the imploding pump source from the lasant. We are also developing a converter technology for examining the Na-Ne line matching scheme. Design considerations and some computational results are presented

Z-PINCH IMPLOSION DRIVEN X-RAY LASER RESEARCH

In experiments performed during the past two years on Proto II (a 10-TW pulsed-power accelerator), we imploded annular plasmas onto thin-walled annular x-ray laser targets in order to create a radiation pump source for x-ray laser physics studies. This Z-pinch must be axially uniform and must efficiently produce the pump radiation without destroying the laser medium on the cylindrical axis of symmetry. To characterize the pump source x-rays and lasant conditions, we regularly field a large number of x-ray diagnostics. In recent experiments, we produced over 15 kJ of ≥1-keV pump radiation with an imploding neon gas-puff load. We are considering both recombination and resonance-pumped x-ray laser schemes

Mass distribution of hydrodynamic jets produced on the national ignition facility

The production of supersonic jets of material via the interaction of a strong shock wave with a spatially localized density perturbation is a common feature of inertial confinement fusion and astrophysics. The spatial structure and mass evolution of supersonic jets has previously been investigated in detail [J. M. Foster et. al, Phys. Plasmas 9, 2251 (2002) and B. E. Blue et. al, Phys. Plasmas 12, 056312 (2005)]. In this paper, the results from the first series of hydrodynamic experiments will be presented in which the mass distribution within the jet was quantified. In these experiments, two of the first four beams of NIF are used to drive a 40 Mbar shock wave into millimeter scale aluminum targets backed by 100 mg/cc carbon aerogel foam. The remaining beams are delayed in time and are used to provide a point-projection x-ray backlighter source for diagnosing the structure of the jet. Comparisons between data and simulations using several codes are presented