Absolute x-ray yields from laser-irradiated germanium-doped low-density aerogels

Journal Article · Fri May 15 00:00:00 EDT 2009 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.3140041· OSTI ID:21277100

Fournier, K B; Satcher, J H; May, M J; Poco, J F; Sorce, C M; Colvin, J D; Hansen, S B; MacLaren, S A; Moon, S J; Davis, J F ^[1]; Girard, F; Villette, B; Primout, M; Babonneau, D ^[2]; Coverdale, C A; Beutler, D E ^[3]

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1. Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)
2. Commissariat a l'Energie Atomique-Direction des Application Militaires (CEA/DAM), Ile-de-France, F91297 Arpajon (France)
3. Sandia National Laboratory, Albuquerque, New Mexico 87185 (United States)

The x-ray yields from laser-irradiated germanium-doped ultra-low-density aerogel plasmas have been measured in the energy range from sub-keV to {approx_equal}15 keV at the OMEGA laser facility at the Laboratory for Laser Energetics, University of Rochester. The targets' x-ray yields have been studied for variation in target size, aerogel density, laser pulse length, and laser intensity. For targets that result in plasmas with electron densities in the range of {approx_equal}10% of the critical density for 3{omega} light, one can expect 10-11 J/sr of x rays with energies above 9 keV, and 600-800 J/sr for energies below 3.5 keV. In addition to the x-ray spectral yields, the x-ray temporal waveforms have been measured and it is observed that the emitted x rays generally follow the delivered laser power, with late-time enhancements of emitted x-ray power correlated with hydrodynamic compression of the hot plasma. Further, the laser energy reflected from the target by plasma instabilities is found to be 2%-7% of the incident energy for individual beam intensities {approx_equal}10{sup 14}-10{sup 15} W/cm{sup 2}. The propagation of the laser heating in the target volume has been characterized with two-dimensional imaging. Source-region heating is seen to be correlated with the temporal profile of the emitted x-ray power.

• OSTI ID: 21277100
• Journal Information: Physics of Plasmas, Vol. 16, Issue 5; Other Information: DOI: 10.1063/1.3140041; (c) 2009 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
DENSITY
DOPED MATERIALS
ELECTRON DENSITY
GELS
GERMANIUM
HOT PLASMA
LASER-RADIATION HEATING
PLASMA INSTABILITY
X RADIATION