The effect of artificially close boundaries on numerical simulations of the instability and evolution of barium clouds

This note is a critique of a source of errors in the work of Lloyd and Haerendel (1973). The computational region in which they place their cloud is small, and the artificially close boundaries introduce spurious electric fields. Instability growth rates are artificially reduced, and at late times, spurious maximums and minimums appear on the potential contour diagrams. The density contours may exhibit artificial spreading or compression. In an analytic study of a one-dimensional slab model with artificially close boundaries we have reproduced some of the spurious properties.