Pinhole closure measurements

David Milam; James E. Murray; Kent G. Estabrook; Charles D. Boley; Walter D. Sell; Norman D. Nielsen; R. K. Kirkwood; Yuri A. Zakharenkov; Bedros B. Afeyan

doi:10.1117/12.354164

23 July 1999 Pinhole closure measurements

David Milam, James E. Murray, Kent G. Estabrook, Charles D. Boley, Walter D. Sell, Norman D. Nielsen, R. K. Kirkwood, Yuri A. Zakharenkov, Bedros B. Afeyan

Author Affiliations +

Proceedings Volume 3492, Third International Conference on Solid State Lasers for Application to Inertial Confinement Fusion; (1999) https://doi.org/10.1117/12.354164
Event: Third International Conference on Solid State Lasers for Application to Inertial Confinement Fusion, 1998, Monterey, CA, United States

Abstract

Spatial-filter pinholes and knife-edge samples were irradiated in vacuum by 1053-nm, 5-20 ns pulses at intensities to 500 GW/cm². The knife-edge samples were fabricated of plastic, carbon, aluminum, 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 al 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 V_2(pi ) of the contour for a 2(pi) phase shift. To within experimental error, V_2(pi ) was constant during irradiation at a particular intensity, and it increased linearly with intensity for intensities < 300 GW/cm². For metal samples V_2(pi ) 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 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.

Citation Download Citation

David Milam, James E. Murray, Kent G. Estabrook, Charles D. Boley, Walter D. Sell, Norman D. Nielsen, R. K. Kirkwood, Yuri A. Zakharenkov, and Bedros B. Afeyan "Pinhole closure measurements", Proc. SPIE 3492, Third International Conference on Solid State Lasers for Application to Inertial Confinement Fusion, (23 July 1999); https://doi.org/10.1117/12.354164

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available