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Foundations of VISAR analysis

Dolan, Daniel H.

The Velocity Interferometer System for Any Reflector (VISAR) is a widely used diagnostic at Sandia National Laboratories. Although the operating principles of the VISAR are well established, recently deployed systems (such as the fast push-pull and air delay VISAR) require more careful consideration, and many common assumptions about VISAR are coming into question. This report presents a comprehensive review of VISAR analysis to address these issues. Detailed treatment of several interferometer configurations is given to identify important aspects of the operation and characterization of VISAR systems. The calculation of velocity from interferometer measurements is also described. The goal is to derive the standard VISAR analysis relationships, indicate when these relationships are valid, and provide alternative methods when the standard analysis fails.