A comparison of aluminum and nickel wire array z-pinches and aluminium exploding single wires

Summary form only given. An extensive aluminum wire array experiment has been performed. Wire arrays of 6-25-mm diameter have been imploded on the 6-TW Double-EAGLE generator. With the masses adjusted so that the implosion time was between 85 and 95 ns, an optimum aluminum K-shell yield of 30 kJ was obtained with an array diameter of 12.5 mm. Analyses were performed which indicate that the kinetic energy per ion for this implosion was 18 keV, which is greater than the 12 keV required to ionize to heliumlike aluminum if radiation losses are neglected. Under this condition, the total implosion kinetic energy is comparable to the radiated K-shell energy but very much less than the total radiated yield. Furthermore, comparing the measured K-shell yield to those predicted by a one-dimensional radiation-magnetohydrodynamic code, which only assumes motional kinetic energy as the energy source, indicates that kinetic energy alone cannot account for the radiation. To explain this, other heating mechanisms such as ohmic heating, 2-D effects, or plasma bouncing can be invoked. Data from the time- and space-resolved X-ray and spectroscopic diagnostics were obtained in an effort to extract pointers to the other heating mechanisms. In particular, time-resolved crystal spectra were used to study the variation of plasma electron temperature and density in time when analyzed with the appropriate CRE models