Transient gas motion in nuclear-reactor-pumped lasers: Computational and experimental results
In some types of nuclear-reactor-pumped lasers, the fission fragments that are used to excite gaseous lasing species heat the gas in a spatially nonuniform manner. This heating nonuniformity induces transient gas motion, which results in density and refractive-index gradients that affect the laser's optical behavior. A model of the transient gas motion is developed using the acoustic filtering methodology, which neglects the spatial variation of the pressure. This model incorporates the effect of spatially varying gas density on fission-fragment heating. Gas motion out of the laser cell into small, rapidly cooled regions is treated as a volumetric mass loss distributed over the laser cell. Although these regions have a relatively small fraction of the total volume, a large amount of gas can flow into them during the heating because of the rapid cooling therein. This gas removal from the cell during pumping, neglected in previous analyses, is important because fission-fragment heating is strongly dependent on local gas density. To quantify the laser's optical behavior, experiments are performed in which a probe laser beam is passed through the laser cell. This probe beam acquires a wavefront distortion from the refractive-index gradients and is imaged onto a wavefront slope sensor, which yields temporally and spatially resolved measurements of the angular deflection (wavefront slope) of the probe laser beam. Experimental and model results for this quantity exhibit reasonably good agreement over a wide range of pressures and heating amplitudes. 14 refs., 12 figs.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (United States)
- Sponsoring Organization:
- DOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 5630282
- Report Number(s):
- SAND-91-1441C; CONF-920605--1; ON: DE92002357
- Country of Publication:
- United States
- Language:
- English
Similar Records
Refractive index gradients in nuclear-reactor-pumped lasers: Gasdynamic effects
Gasdynamic phenomena in nuclear-reactor-pumped lasers
Related Subjects
426002* -- Engineering-- Lasers & Masers-- (1990-)
99 GENERAL AND MISCELLANEOUS
990200 -- Mathematics & Computers
COMPUTER CALCULATIONS
COMPUTERIZED SIMULATION
DENSITY
FLUIDS
GAS LASERS
GASES
LASERS
MATHEMATICAL MODELS
MOTION
NEUTRON FLUX
NUCLEAR PUMPING
PHYSICAL PROPERTIES
PRESSURE DEPENDENCE
PUMPING
RADIATION FLUX
REACTORS
SIMULATION
THERMODYNAMICS