Analytical results for the resistive Rayleigh-Taylor instability in rail launcher accelerated plasmas

We obtain analytical results for the Rayleigh-Taylor instability in finite conductivity accelerated plasma arcs. Our results apply to the case /spl upsi//sub T//sup 2//a/spl Lscr//spl Gt/1, where /spl Lscr/ is the plasma length, a is the acceleration, and /spl upsi//sub T/ is the thermal speed. This case is valid in electromagnetic rail launchers where the projectile mass is large compared to the plasma mass. The conductivity /spl sigma/ enters via a magnetic Reynolds number R=/spl sigma//spl mu/(a/spl Lscr//sup 3/)/sup 1/2 /. The fourth order mode equation is solved analytically using an asymptotic WKB expansion in 1/R. We find the first order 1/R correction to the classical Rayleigh-Taylor dispersion relation for wavenumber K with 1/spl Lt/KL/spl Lt/R/sup 2/.<>