Investigation of the dynamics of expansion of the near-surface light erosion plasma formed during the evaporation of a material by broadband high-brightness radiation

摘要

The dynamics of the vapor-plasma flows formed at impact of erosion type magnetoplasma compressor (MPC) discharge radiation on Ti, Al and PTFE targets with use of methods of a holographic interferometry and schlieren photos (Toepler's scheme in the light field mode) is investigated. In the schlieren and interferogram photos, zones characteristic of the studied process of radiation interaction with matter are well visible: the gas-dynamic evaporation mode is realized (plasma piston mode), there is a shock wave in the gas, the contact boundary between the shock-compressed gas and the vapor plasma. The interferograms analysis indicates that the regime of developed evaporation is preceded by a regime of diffusion evaporation. On the interferograms above the targets at different distances from the radiation source (from the MPC), we observe 3 types of gas-dynamic perturbations: an acoustic wave, a simple wave (Riemann wave), and a shock wave. Qualitative and quantitative description of processes in these zones is discussed in the report. The effect of the radiation spectral composition (we use the method of gas spectral selection), the targets materials, and the degree of surface treatment on the evaporation is shown experimentally.