Analytical and computational modeling of small laser-driven flyer plates
This work addresses the behavior of a small flyer plate, driven from the end of an optical fiber by the action of a pulse of laser energy. Both analytical and computational techniques have been used to obtain a sound understanding of the phenomena involved. For this analysis, the energy deposition in the metal is assumed to be exponential. The part of the energy deposited that is useful in driving the flyer, is the part having greater intensity than that required to product vaporization, as shown. The equations expressing energy conservation relating to that figure are given, along with the parameterization of the effective deposition depth by the laser absorption coefficient and the thermal conductivity. Solution of these equations is done utilizing experimental data to supply the parameters r, the fraction of energy lost to reflection and radiation (assumed constant), and the ratio of the vaporization energy to effective absorption coefficient. Several consequences of the model, including high-fluence scaling of both the flyer velocity and coupling efficiency, and the moderate-fluence behavior of the impulse coupling coefficient are shown. Comparisons of model results fro the late-time flyer velocity with data from experiments using aluminum flyers are shown. Model results for three different metal foils are shown. Note that in all cases, the magnesium flyer outperforms both the aluminum and copper flyers. The numerical modeling of these experiments has utilized the LASNEX hydrocode (Figure 10), which has some (but not all) of the features needed for the modeling of laser deposition in the metal foils.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 10111900
- Report Number(s):
- SAND--91-2182C; CONF-9110282--3; ON: DE92004207
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
450000
661300
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
99 GENERAL AND MISCELLANEOUS
990200
ACCELERATION
ALUMINIUM
ANALYTICAL SOLUTION
C CODES
COPPER
FIBER OPTICS
FOILS
HYDRODYNAMICS
L CODES
LASER-PRODUCED PLASMA
MAGNESIUM
MATHEMATICAL MODELS
MATHEMATICS AND COMPUTERS
MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE
OTHER ASPECTS OF PHYSICAL SCIENCE
THERMAL CONDUCTIVITY