The twelve-channel 'Iskra-5' iodine laser facility was updated to enable investigations in the regime of high-power two-pulse target irradiation, when the second pulse is delayed by a time of up to 10 μs relative to the first one and possesses an energy equal to or comparable with the energy of the first pulse.
Results are presented from experimental and theoretical studies of a glowing plasma object emerging behind a shock front that propagates through the background gas at a pressure of p 0 = 6 torr after laser irradiation of a hollow spherical target. The results of calculations are compared to the experimental results obtained in the MKV-4 device (a component of the Iskra-5 facility).
The technique and results of measurements of the sensitivity of an inductive sensor of small displacements are described. The sensitivity was measured by optical-interference monitoring of the displacement of a metallic reflector fixed to a piezoceramic element. It is shown that this technique ensures the calibration of an eddy-current sensor to an accuracy of no worse than 1 μm.
In doing research on the turbulent mixing (TM) of two gases different in density, it is of great interest to study experimentally the 3D density distribution pattern of chemically nonreactive gases in the TM zone. For this purpose, noncontact and, particularly, optical techniques to obtain experimental data may be attractive. This article discusses the possibility of using pulsed laser interferometry in this application. Based on this technique, the experiment should result in the mixture density distribution integrated along the light path. Requirements for high-quality interference patterns have been analyzed in application to typical experimental conditions, to show that they may be produced with specific restrictions set on the mixture constitution. Generally, the TM zone has no symmetry. Therefore, the problem of reconstructing 3D density distributions (TDD) of gases can be solved by sufficiently providing many TM zone integral projections (or aspects). It is technically difficult and expensive to achieve this large number of aspects ( N > 10). Therefore, it is essential that a reconstruction method be selected to allow the solution of the problem with the least possible number of aspects. Given that the experiment data are incomplete, the reconstruction methods that are based on the concept of maximum data entropy did well. Information a priori about the solution to be sought for an isobaric gas mixture is that its each constituent has invariable density. Thus, a functional data entropy can be defined that is similar to Fermi gas in statistical physics. An algorithm has been suggested for reconstruction as a modified maximum-bounded entropy procedure (Bashurin et al. 1995). This makes reasonable good reconstruction achievable even with as few aspects as N = 4. Experiments on the study of TM of a propane jet in air using a four-aspects laser interferometer were provided and reconstruction of propane concentration distribution was conducted. The results allow determination of the TM zone spectral characteristics.