Ferraro's Contribution to Ionospheric Research

Abstract

Hfor the electron density N at altitude z (measured in units of scale height H) and time t. The diffusion coefficient D turns out to be inversely proportional to the collision frequency of ions and hence to the number density of neutral particles. It follows that D increases upwards exponentially. It is assumed for simplicity that the ions and neutral particles have the same constant scale height. Of the remaining terms in the equation, q represents the rate of electron production and L the rate of loss. The application of the diffusion equation to the F2 layer was hindered for several years because the nature of the loss process was not fully understood. Ratcliffe et at. (1956) gave justification for assuming an attachment-type law L = Be-’N, where /3 is a constant. There remained some doubt as to the most appropriate boundary condition to apply at z = 00. The most natural assumption, for a supposedly static region, was that the flux of ionization should vanish at great height. The resulting mathematical models were in fair agreement with the diurnal behaviour of hmF2 and NmF2 in middle latitudes at times of low geomagnetic activity.