Measurement of plasma characteristic parameters of copper foil explosion using interferometry

The accurate testing of plasma temperature and electron density and shock wave pressure during an electroburst in a copper foil transducer is critical for the characterization of the detonation performance of its elements. In this paper, the sequence of interferograms during the detonation of a copper foil transducer is captured at a frame rate of 3×10⁶ <i>f</i> <i>p</i> <i>s</i> in conjunction with Mach-Zehnder interferometry and high-speed photography, and the results clearly demonstrate the propagation of the shock wave wavefront and plasma. The phase differences disturbed by plasma are extracted using the Fourier transform method, and the refractive index distributions are reconstructed with the Abel algorithm. Subsequently, based on the refractive index models of the shock wave and plasma, the shock wave pressure and plasma temperature and electron density are partitioned and reconstructed. Results show that the maximum shock wave pressure in the detonation of the copper foil transducer element is 1.297 atm, the maximum plasma temperature is 16,280 K, and the maximum plasma electron density is 2.134×10¹⁷ <i>c</i> <i>m</i> ^-3. This study provides a theoretical and technical foundation for the detonation performance testing of pyrotechnic energy-conversion components.