Interferogram analysis of X-pinch plasmas with a synthetic dark-field Schlieren image

The Mach-Zehnder interferometer and dark-field Schlieren imaging systems are developed to diagnose high electron densities of the X-pinch plasmas. Interferogram analysis can be challenging due to stiff electron density gradients of the X-pinch plasmas. This stiff gradient results in complex fringe patterns which may lead to miscounted indices of the fringes, and even refraction losses. To address these challenges, the geometrical acceptance angle of the imaging system is increased to reduce the refraction losses caused by the X-pinch plasmas. This is achieved by using physically larger optics. Results show that the imaging systems can detect higher line-integrated electron densities. Additionally, to verify the reliability of interferogram analysis results, a synthetic dark-field Schlieren image generated based on the interferogram is qualitatively compared to the measured dark-field Schlieren image which is simultaneously taken with the interferogram. Practicality of the synthetic Schlieren images is examined by comparing them with the measured Schlieren images.