Mixtures of lons in the Wind-Shear Theory of Sporadic e

The wind-shear theory of sporadic E predicts that when only one ion species is present, and the peak electron density is a factor R times the ambient, the minimum electron density is 1/R of the ambient. With two species present, the minimum electron density is greater than this and approaches the ambient when the ratio of recombination coefficients is large and the more rapidly recombining ion predominates in the ambient ionsphere. The peak density depends only on the recombination coefficient of the slowly recombining ion and the gradient in the vertical drift motion. The problem of nighttime sporadic E is considered, but no satisfactory solution is offered