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Author McEachern, R. L. ♦ Moore, C. E. ♦ Wallace, R. J.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword PLASMA PHYSICS AND FUSION ♦ LASER TARGETS ♦ LASER IMPLOSIONS ♦ INERTIAL CONFINEMENT ♦ RAYLEIGH-TAYLOR INSTABILITY ♦ COMPUTERIZED SIMULATION ♦ MEASURING INSTRUMENTS ♦ MICROSCOPES ♦ DESIGN ♦ PERFORMANCE
Abstract Rayleigh--Taylor instabilities during implosions of inertially confined fusion capsules affect capsule performance. During acceleration, surface imperfections grow and can, if large enough, lead to an asymmetric implosion or even shell breakup. For this reason, characterizing the topography of target capsules is extremely important. We have developed a profilometer based on an atomic force microscope combined with a precision rotary air bearing. Averaged one-dimensional (1D) surface height power spectra obtained with this instrument are converted to two-dimensional mode spectra that are used as input to hydrodynamic simulations. We describe the design of the system and its performance in terms of runout and repeatability. We also discuss the simulation of these measurements and the statistics involved in averaging 1D power spectra. Finally, we show the application of this measurement technique to capsules whose surfaces have been modified by laser ablation, resulting in a well-defined surface topography. This special case provides an excellent test for the system since the expected results are exactly calculable. {copyright} {ital 1995} {ital American} {ital Vacuum} {ital Society}
ISSN 07342101
Educational Use Research
Learning Resource Type Article
Publisher Date 1995-05-01
Publisher Place United States
Journal Journal of Vacuum Science and Technology, A
Volume Number 13
Issue Number 3


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