Conical wire array experiments on the zebra generator

Abstract

Summary form only given. We present the results of recent conical wire array experiments on the Zebra generator. In this paper we will discuss the dynamics of conical wire array implosions, particularly the zippered implosion which results from the tapering of the array and the formation of a magnetic bubble near the small diameter electrode (the cathode). The implosion characteristics of a given axial position (and hence diameter) of the conical wire array will be compared to equivalent diameters of cylindrical wire arrays (e.g. size, temperature and density of the stagnated column). Results for Al and Cu conical wire arrays will be discussed. These experiments also investigate the axial mass transport in conical wire arrays. Spectroscopic dopants are coated as a thin band onto each wire and a time integrated, axially resolved spectrometer is used to study which axial positions this tracer material reaches. Results are consistent with expectations that, due to the geometry, this coating will be transported further axially than in cylindrical wire array experiments. The experimental data will be compared to 3D MHD simulations of the conical array implosions in which the position of the coating material is tracked through the computational grid. The effect of this coating band on the dynamics of the conical wire array will also be discussed