Wavelength dependence of the linear growth rate of the Es layer instability

It has recently been shown, by computation of the linear growth rate, that midlatitude sporadic-E (Es) layers should be subject to a large scale electrodynamic instability. This instability is a logical candidate to explain certain frontal structuring events, and polarization electric fields, which have been observed in Es layers by ionosondes, by coherent scatter radars, and by rockets. As such it provides an alternative, or complementary mechanism to that proposed by Larsen, of a Kelvin-Helmholtz instability in the Neutral wind, for explaining more or less the same set of observations. However, the original growth rate derivation assumed an infinitely thin Es layer, and therefore did not address the short wavelength cutoff. Also, the same derivation ignored the effects of F region loading, which is a significant wavelength dependent effect. Herein is given a generalized derivation that remedies both these short comings, and thereby allows a prediction for the wavelength dependence of the linear growth rate, as well as computations of various threshold conditions. The wavelength dependence of the linear growth rate is compared with observed periodicities, and the role of the zeroth order meridional wind is explored.