Time evolution of Z-pinch dynamics and radiative characteristics of wire arrays on zebra at UNR

摘要

We continue to study the physics of wire arrays and to search for more efficient X-ray radiators from wire array Z-pinch plasmas. Two important questions are addressed in this talk. First, what are the main contributions in the total radiation yield? To consider this question, we divided the time interval of the Z-pinch dynamics where wire ablation, implosion, stagnation, and plasma expansion occur in three time zones and studied the radiative and implosion characteristics within each. The second question is how does the distribution of the radiated energy within these three time zones depend on the configuration of the load and wire materials. The experiments were performed on the 1 MA Zebra generator at UNR with a full set of diagnostics that included 10 beam lines. In particular, PCD, XRD, and EUV detectors, X-ray/EUV spectrometers and X-ray pinhole cameras, and laser shadowgraphy were utilized. We collected and analyzed the experimental results from single and nested cylindrical as well as single and double planar wire arrays. A broad range of wire materials were explored from low-Z (Al) to moderate mid-Z (Fe, Ni, and Cu) and higher mid-Z (Mo and Ag). The strong dependence of the distribution of radiation energy between the three zones on the load configuration was observed. Z-pinch dynamics and both X-ray and EUV radiative properties in all three time zones were considered. A precursor plasma in the first zone from cylindrical wire arrays as well as the plasma in the second zone at stagnation from cylindrical and planar wire arrays are discussed. A special emphasis was put on the time evolution of EUV radiation in all three zones and in particular on its substantial value in the third zone after stagnation. Future directions of this work are discussed.