Experiments with a Small Injected Railgun
Abstract
Experiments aimed at gaining insight into the plasma arc and rail damage in railguns are described and discussed. The railgun body was constructed of clear polycarbonate to allow streak photographs of the plasma to be taken. A power-gun injector was used to reduce initial rail damage. The development of the injector and projectiles is described. Rails with plain surfaces, alternating aluminium inserts, and lengthwise insulating stripes were studied. Both aluminium and copper foils were used for plasma initiation. The results from the experiments enable plasma formation to be explained in terms of the vaporization energy of the foil and material taken up from the bore. Magnetic pick-up coils were used to study plasma length and current distribution and the theory of the coils and a look-up table of calculated waveforms is given. A non- metallurgical study of rail damage has been made, and damage mechanisms are identified. A qualitative model of the plasma is described, in which two current conduction modes at the rail-plasma boundary are identified. These are an ohmic (direct contact) mode, and an arc-root mode. The severe rail-surface damage observed is thought to be due to boundary conduction in the ohmic mode rather than to the current-carrying arc-roots leaving and entering the rails. Keywords: Railgun; Optical fibers; Injectors; Electric guns: Electromagnetic launcher; Rail damage. Australia.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1987
- Accession Number
- ADA200995
Entities
People
- D. F. Stainsby
- D. R. Sadedin
Organizations
- Defence Science and Technology Group