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Scaling Relations for Laser Damage Initiation Craters.

DE200515013198

Publication Date	2000
Personal Author	Feit, M. D.; Hrubesh, L. W.; Rubenchik, A. M.; Wong, J.
Page Count	14
Abstract	General physical relations connect the expected size and depth of laser damage induced craters to absorbed laser energy and to the strength of the material. In general, for small absorbers and 'instantaneous' energy release, one expects three regions of interest. First is an inner region in which material is subjected to high pressure and temperature, pulverized and ejected. The resultant crater morphology will appear melted. A second region, outside the first, exhibits material removal due to spallation, which occurs when a shock wave is reflected at the free surface. The crater surface in this region will appear fractured. Finally, there is an outermost region where stresses are strong enough to crack material, but not to eject it. These regions are described theoretically and compared to representative observed craters in fused silica.
Keywords	Lasers Damage Scaling Craters Spallation Optics Morphology Shock waves Nuclear explosions Cracks Defects Silica Stresses
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Lawrence Livermore National Lab., CA.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200604

Scaling Relations for Laser Damage Initiation Craters.

Scaling Relations for Laser Damage Initiation Craters.
DE200515013198

Publication Date	2000
Personal Author	Feit, M. D.; Hrubesh, L. W.; Rubenchik, A. M.; Wong, J.
Page Count	14
Abstract	General physical relations connect the expected size and depth of laser damage induced craters to absorbed laser energy and to the strength of the material. In general, for small absorbers and 'instantaneous' energy release, one expects three regions of interest. First is an inner region in which material is subjected to high pressure and temperature, pulverized and ejected. The resultant crater morphology will appear melted. A second region, outside the first, exhibits material removal due to spallation, which occurs when a shock wave is reflected at the free surface. The crater surface in this region will appear fractured. Finally, there is an outermost region where stresses are strong enough to crack material, but not to eject it. These regions are described theoretically and compared to representative observed craters in fused silica.
Keywords	Lasers Damage Scaling Craters Spallation Optics Morphology Shock waves Nuclear explosions Cracks Defects Silica Stresses
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Lawrence Livermore National Lab., CA.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200604