Interchange Instability in Railgun Arcs.
Abstract
Plasma arcs used to accelerate projectiles in railguns are examined to determine their susceptibility to the Rayleigh Taylor interchange instability. The model used is similar to that developed by Tsai, Liskow, and Wilcox, although a number of modifications are made and discussed. Numerical solutions of the appropriate eigenvalue problem suggest that the plasma is unstable for any non zero acceleration of the projectile. Furthermore, for the dispersion curves calculated the growth rates of the short-wavelength modes are accurately approximated by the well-known expression omega = sq. rt. (k a sub 0), were k is the wavenumber of the perturbation and a sub 0 is the acceleration. Growth rates calculated for typical experimental parameters indicate that the instability should be seen in experiments of interest. Some effort to reconcile the results with existing experimental data is made but the need for more work, both theoretical and experimental, is indicated. Keywords: Railgun arc; Plasma instability; Rayleigh Taylor instability; Interchange instability; Electromagnetic propulsion.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1987
- Accession Number
- ADA177508
Entities
People
- John D. Powell
Organizations
- Ballistic Research Laboratory