U.S. Department of EnergyOffice of Scientific and Technical Information
Pinhole closure measurements
Abstract
Spatial-filter pinholes and knife-edge samples were irradiated in vacuum by 1053-nm, 5-20 ns pulses at intensities to 500 GW/cm. The knife-edge samples were fabricated of plastic, carbon, ahnuinum, stainless steel, molybdenum, tantalum, gold and an absorbing glass. Time-resolved two-beam interferometry with a 40-ns probe pulse was used to observe phase shifts in the expanding laser-induced plasma. For all of these materials, at any time during square-pulse irradiation, the phase shift fell exponentially with distance from the edge of the sample. The expansion was characterized by the propagation velocity V2x of the contour for a 2(pi) phase shift. To within experimental error, V2x, was constant during irradiation at a particular intensity, and it increased linearly with intensity for intensities <300 GW/cn2. For metal samples, V, exhibited an approximate M-0.5 dependence where M is the atomic mass. Plasmas of plastic, carbon and absorbing glass produced larger phase shifts, and expanded more rapidly, than plasmas of the heavy metals. The probe beam and interferometer were also used to observe the closing of pinholes. With planar pinholes, accumulation of on-axis plasma was observed along with the advance of plasma away from the edge of the hole. On-axis closure was not observed in square, 4-leafmore »
- Authors:
- Publication Date:
- Research Org.:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Org.:
- USDOE Office of Defense Programs (DP)
- OSTI Identifier:
- 3396
- Report Number(s):
- UCRL-JC-129854
DP0212000; ON: DE00003396
- DOE Contract Number:
- W-7405-Eng-48
- Resource Type:
- Conference
- Resource Relation:
- Conference: Third Annual International Conference on Solid State Lasers Application (SSLA) for Inertial Confinement Fusion (ICF), Monterey, CA, June 7-12, 1998
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 70 PLASMA PHYSICS AND FUSION; Carbon; Aluminum; Iron; Molybdenum; Tantalum; Closures; Apertures
Citation Formats
Afeyan, B B, Boley, C D, Estabrook, K G, Kirkwood, R K, Milam, D, Murray, J E, Nielsen, N D, Sell, W D, and Zakharenkov, Y A. Pinhole closure measurements. United States: N. p., 1998.
Web.
Afeyan, B B, Boley, C D, Estabrook, K G, Kirkwood, R K, Milam, D, Murray, J E, Nielsen, N D, Sell, W D, & Zakharenkov, Y A. Pinhole closure measurements. United States.
Afeyan, B B, Boley, C D, Estabrook, K G, Kirkwood, R K, Milam, D, Murray, J E, Nielsen, N D, Sell, W D, and Zakharenkov, Y A. 1998.
"Pinhole closure measurements". United States. https://www.osti.gov/servlets/purl/3396.
@article{osti_3396,
title = {Pinhole closure measurements},
author = {Afeyan, B B and Boley, C D and Estabrook, K G and Kirkwood, R K and Milam, D and Murray, J E and Nielsen, N D and Sell, W D and Zakharenkov, Y A},
abstractNote = {Spatial-filter pinholes and knife-edge samples were irradiated in vacuum by 1053-nm, 5-20 ns pulses at intensities to 500 GW/cm. The knife-edge samples were fabricated of plastic, carbon, ahnuinum, stainless steel, molybdenum, tantalum, gold and an absorbing glass. Time-resolved two-beam interferometry with a 40-ns probe pulse was used to observe phase shifts in the expanding laser-induced plasma. For all of these materials, at any time during square-pulse irradiation, the phase shift fell exponentially with distance from the edge of the sample. The expansion was characterized by the propagation velocity V2x of the contour for a 2(pi) phase shift. To within experimental error, V2x, was constant during irradiation at a particular intensity, and it increased linearly with intensity for intensities <300 GW/cn2. For metal samples, V, exhibited an approximate M-0.5 dependence where M is the atomic mass. Plasmas of plastic, carbon and absorbing glass produced larger phase shifts, and expanded more rapidly, than plasmas of the heavy metals. The probe beam and interferometer were also used to observe the closing of pinholes. With planar pinholes, accumulation of on-axis plasma was observed along with the advance of plasma away from the edge of the hole. On-axis closure was not observed in square, 4-leaf pinholes.},
doi = {},
url = {https://www.osti.gov/biblio/3396},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jul 20 00:00:00 EDT 1998},
month = {Mon Jul 20 00:00:00 EDT 1998}
}