A Study of Window Focusing Effects on Laser Ignition for Medium-Caliber Systems

Report No. ARL-TR-2743
Authors: Jeffrey B. Morris and Richard A. Beyer
Date/Pages: May 2002; 25 pages
Abstract: One proposed implementation of medium-caliber laser ignition employs a focusing ball to replace the conventional electric primer. The effects of ball size and igniter stand-off distance have been characterized experimentally with black powder pellets. Ignition threshold and delay experiments were carried out using 4-mm and 6-mm diameter glass beads with standoffs up to 1.5 mm. Ray tracing was used to model the energy distribution of a top-hat beam profile refracted through a focusing ball. Results of the study indicate that the tighter focus of the 4-mm bead can reduce the required laser pulse energy with little effect on the ignition delay.
Distribution: Approved for public release
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Last Update / Reviewed: May 1, 2002