Stability of Magnetically Imploded Liners for High Energy Density Experiments
Abstract
Magnetically imploded cylindrical metal shells (z-pinch liners) are attractive drivers for a wide variety of hydrodynamics and material-properties experiments. The ultimate utility of liners requires the acceleration of near-solid density shells to velocities exceeding 20 km/sec while retaining good azimuthal symmetry and axial uniformity. Two pulsed power systems (Ranchero and Atlas), currently operational or under development at Los Alamos, provide electrical energy adequate to accelerate ~50 g liners to 1- 2 MJ/cm kinetic energy. As in all z-pinches, the outer surface of a magnetically imploded liner is unstable to magnetohydrodynamic Rayleigh-Taylor (MHD-RT) modes during acceleration. Therefore, initially small imperfections can grow large-scale distortion making liners unusable for many experiments. On the other hand, material strength in the liner should, from first principles, reduce the growth rate of RT modes, and strength can render some combinations of wavelength and amplitude analytically stable. The growth of instabilities in both soft aluminum liners and in high strength aluminum alloy liners has been studied analytically, computationally, and experimentally at liner kinetic energies up to 100 KJ/cm on the Pegasus capacitor bank using driving currents up to 12 MA.
- Publication:
-
Megagauss Magnetic Field Generation, Its Application to Science and Ultra-High Pulsed-Power Technology
- Pub Date:
- November 2004
- DOI:
- 10.1142/9789812702517_0099
- Bibcode:
- 2004mmfg.conf..473R