Plastic plasma influence on formation of laser-produced copper plasma jet

摘要

This paper is aimed at investigations of interaction of áxially symmetrical light (plastic - CH) plasma with heavy (Cu) plasma. It demonstrates that a relatively thin plastic plasma envelope can compress the Cu plasma and control the Cu-jet formation. The use of axially symmetrical composed targets consisting of both materials makes it possible to create different plasma stream configurations (very narrow jet, pipe, and cone). The experiment was carried out with the Prague Asterix Laser System (PALS) iodine laser. The laser provided a 250-ps pulse with energy of 130 J at the third harmonic frequency (λ_3 =0.438 μm). For measurements of the electron density evolution a three frame interferometric system was employed. Theoretical analysis of the experimental results allows us to conclude that difference in plasma pressure related to plasmas with low (CH) and high (Cu) atomic number results from essential differences in the plasma expansion features between these plasmas. The ratio of the pressures of plastic and copper plasmas was evaluated to be equal to 1.35.