Sporadic E in Middle Latitudes—a Reply

Abstract

MY communication¹ suggested that sporadic E layers are accompanied by, not formed by, discontinuities in the vertical motion of the neutral gas. The horizontal motion of the neutral gas also plays an important part in the hypothesis I outlined. The vertical drift velocity of ionization, as given by equation (10)¹, is The coefficients a_x, a_y, which are proportional to the horizontal component of the magnetic field, undergo abrupt changes at a discontinuity of the kind contemplated in my communication. The increments of a_x and a_y as well as that of u_z contribute to the increment of w across a layer of discontinuity. There is no obvious reason why the last contribution should be dominant, except at high geomagnetic latitudes. Thus the observations cited by Whitehead^2,3 seem to support my hypothesis.