Difficulty associated with wind-shear theory of sporadicE

It is concluded that the metallic ion content of the E region is extremely variable in time; this variation is reflected in the variability of sporadic E. However, the production of metallic ions cannot be so variable; therefore the loss rate must be variable. The most efficient loss mechanism is the corkscrew mechanism that transports the metallic ions into the lower E or D region. By switching this mechanism on and off, the metallic ion content can be changed. Partial reflection of the gravity waves that themselves give the wind shear is suggested as a switching mechanism. There is direct evidence that this does happen. A reversed corkscrew that transports ions upward may sometimes be possible. However, the theory has a major defect in that it predicts most sporadic E where the horizontal component of the earth's field is least, which is just the opposite of what is observed.