Observations of Ablation Dynamics in Wire-Array $Z$ -Pinch Experiments on the Llampüdkeñ Generator

Wire-array Z-pinch experiments have been performed on the Llampüdkeñ generator (~470 kA in ~410 ns) [Chuaqui et al., Laser Part. Beams 15, 241 (1997)] using an overmassed load of aluminum wires. Time-resolved optical laser schlieren and extreme ultraviolet imaging were used in order to study the plasma ablation dynamics. The results show the formation and subsequent ablation of plasma from the wires, followed by the appearance of a precursor plasma column on the axis. According to these results and to the rocket model of wire ablation, an ablation velocity of (1.7-2.6) × 10⁵ m/s is estimated, which is larger than those obtained in faster generators. Additionally, the main resemblances and differences with previous experiments are presented, allowing in this way to open the study of this configuration in smaller scale machines.