The Frozen Deuterium Fiber Revisited on the Z-Pinch Initiation Facility (ZIF)

The Z-Pinch Initiation Facility (ZIF) was built to investigate the effect of initial conditions (e.g., rate of voltage rise) on the stability of a dense Z-pinch formed from a frozen deuterium fiber. The motivation was work initially performed in 1987 by the Naval Research Laboratory (NRL) and Los Alamos National Laboratory (LANL) that reported stability far longer than predicted by magnetohydrodynamic (MHD) theory. NRL observed stability as long as the current was rising, up to 640kA and 130ns. ZIF can drive up to 250kA in 80ns through a single 34-cm-long fiber. In some cases, apparent stability was observed based on visible light streak camera photographs and neutron detectors, which replicated the NRL results. However, in all cases on ZIF, the more extensive diagnostics revealed turbulent <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$m =0$</tex-math> </inline-formula> behavior that dominated the pinch dynamics. Visible light framing images showed short wavelength <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$m =0$</tex-math> </inline-formula> activity (ka~20) as early as 30ns after start of the current. Laser shadowgraphy also showed <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$m =0$</tex-math> </inline-formula> activity. These are consistent with 2-D and 3-D simulations of the experiments. The 2.45-MeV neutrons are produced during the current rise and as much as 120–230ns after current peak. There are still unresolved differences between the ZIF and previous results, which may be due to differences in the Z-pinch current driver. This is one of four papers on ZIF. Others discuss the ZIF pulsed power, the ZIF diagnostic suite, and simulations. An archive of all results will be made available to the public in 2026.