Measurements of Magneto-Rayleigh-Taylor instability growth in solid liners on the 20 MA Z facility
Sinars, Daniel S.; Edens, Aaron E.; Lopez, Mike R.; Smith, Ian C.; Shores, Jonathon S.; Bennett, Guy R.; Atherton, B.W.; Savage, Mark E.; Stygar, William A.; Leifeste, Gordon T.; Slutz, Stephen A.; Herrmann, Mark H.; Cuneo, M.E.; Peterson, Kyle J.; McBride, Ryan D.; Vesey, Roger A.; Nakhleh, Charles N.; Tomlinson, Kurt T.
The magneto-Rayleigh-Taylor (MRT) instability is the most important instability for determining whether a cylindrical liner can be compressed to its axis in a relatively intact form, a requirement for achieving the high pressures needed for inertial confinement fusion (ICF) and other high energy-density physics applications. While there are many published RT studies, there are a handful of well-characterized MRT experiments at time scales >1 {micro}s and none for 100 ns z-pinch implosions. Experiments used solid Al liners with outer radii of 3.16 mm and thicknesses of 292 {micro}m, dimensions similar to magnetically-driven ICF target designs [1]. In most tests the MRT instability was seeded with sinusoidal perturbations ({lambda} = 200, 400 {micro}m, peak-to-valley amplitudes of 10, 20 {micro}m, respectively), wavelengths similar to those predicted to dominate near stagnation. Radiographs show the evolution of the MRT instability and the effects of current-induced ablation of mass from the liner surface. Additional Al liner tests used 25-200 {micro}m wavelengths and flat surfaces. Codes being used to design magnetized liner ICF loads [1] match the features seen except at the smallest scales (<50 {micro}m). Recent experiments used Be liners to enable penetrating radiography using the same 6.151 keV diagnostics and provide an in-flight measurement of the liner density profile.