Electric field in the ionosphere

The anomalously high electron temperature in the lower ionosphere (E-region) cannot be attributed to photoelectrons (Spencer and Brace, 1965). In this report, it is shown that electric fields due to charge separation in the dynamo region provide adequate energy for this purpose. Application of the formula for the velocity distribution of the electrons in crossed electric and magnetic fields (Sen and Wyller, 1960) to the observational data gives electric fields perpendicular to the magnetic field of intensity about 20 to 40 V/km. This is an order of magnitude higher than that obtained in the current dynamo theory. A theory of the origin of the electric field in charge separation due to neutral wind drag is given. The theory leads to the right order of magnitude estimate of the dimensions of ionospheric irregularities. Another likely source for the electric field is where the solar wind meets the magnetosphere (magnetopause). It is shown that a field approx. 1 V/m can build up in the magnetospheric plasma sheath, as in a discharge tube, and be conducted down into the ionosphere along the lines of magnetic force. It is further shown that an electric field of this magnitude can cause the requisite auroral particle acceleration and sheath current for the main phase of magnetic storms. (Author).