Implosion dynamics of a radiative composite Z-pinch

Two-dimensional simulation of a composite Z-pinch was performed by the complete radiative magnetohydrodynamic (MHD) code ZETA including detailed calculation of equations of state, spectral properties of materials, and radiation transport in non-local thermodynamic equilibrium multicharged ions plasma. The initial geometry, the substance components, and the electric current through the Z-pinch were similar to the joint experiment set up JEX-94 at Angara-5 facility. The geometry was: annular argon gas puff with inner and outer diameter of a nozzle cross section, 3 cm and 3.4 cm, respectively, and specific mass of 80 /spl mu/g/cm. Inside it along the axis a foam cylinder 30% KCl in agar-agar with total mass 60 /spl mu/g and diameter 1 mm was put. The initial gas distribution was modelled with a divergence of a jet along the Z-axis. A coupling of the Z-pinch with the electric current generator was modelled by an electrical circuit with a given electromagnetic wave, a resistance, an inductance, and a variable load (Z-pinch) similar to the Angara-5-1 output parameters. During the plasma implosion the total current reached the value of 3 MA at a time of 85 ns from the voltage start. Such current amplitude is much less than through the matched load (up to 4 MA as a rule): The plasma implosion is accompanied by the development of different types of short and long wave instabilities (thermal, radiative, nonisothermal, and MHD Rayleigh-Taylor modes). In this report, the detailed plasma implosion dynamics, the influence of instabilities, and the spectral radiation yield are discussed, and a comparison with the experimental results is done.