Design, fabrication, and operation of a high-energy liner implosion experiment at 16 megamperes

We discuss the design, fabrication, and operation of a liner implosion system at peak currents of 16 MA. Liners of 1100 aluminum, with initial length, radius, and thickness of 4 cm, 5 cm, and 1 mm, respectively, implode under the action of an axial current, rising in 8 /spl mu/s. Fields on conductor surfaces exceed 0.6 MG. Design and fabrication issues that were successfully addressed include: Pulsed Power-especially current joints at high magnetic fields and the possibility of electrical breakdown at connection of liner cassette insulator to bank insulation; Liner Physics-including the angle needed to maintain current contact between liner and glide-plane/electrode without jetting or buckling; Diagnostics-X-radiography through cassette insulator and outer conductor without shrapnel damage to film.

I. Introduction

Pulsed power involves the compression of energy in time and space usually to achieve conditions not accessible by steady delivery of available power. Typical applications of pulsed power include the creation of high-energy-density states of matter for studies of material behavior, equations-of-state, and dynamics [1]. Electromagnetically-driven implosion of cylindrical shells, aka, liners, represents a technique for creating conditions of very high pressure and high speeds . One form of this technique interacts axial current flow in a cylindrical metal liner, with the associated azimuthal magnetic field to create a radial force that implodes the liner. Subsequent impact of the liner with interior target material can drive strong shocks. The present paper discusses in detail the pulsed power and experimental arrangements for operating imploding liners at peak currents of 16 MA. Our experience indicates that success with such experiments depends critically on the details of design and fabrication and we believe that it is, therefore, important to provide a full description of techniques.