Displacement and velocity interferometry for laser-driven shock wave experiments
Abstract
We are developing an active interferometric probe diagnostic that can be used for measuring both surface displacements and surface velocities in laser-driven shock wave experiments. The diagnostic is based around a Michelson interferometer configuration using a novel arrangement that allows either surface displacement (fringe shifts) or velocity (Doppler shifts) to be measured using minor variations of the same optical layout. Assessment of surface displacement prior to shock breakout provides an important measure of target preheat. Measurements of surface velocity after the breakout of low amplitude shocks in solid targets can be used as a means of assessing shock amplitude. In the case of high amplitude shocks driven into transparent targets which ionize the material sufficiently to produce a reflecting front the velocity measurement provides a direct recording of shock speed. We present results using this diagnostic to assess preheat levels and shock amplitudes in laser-driven and holhraum-driven targets. *Work performed under the auspices of the U. S. Department of Energy by the Lawrence Livermore National Laboratory under contract number W-7405-ENG-48.
- Publication:
-
APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- November 1997
- Bibcode:
- 1997APS..DPPpTO203C