Frequency of Collision of Electrons in the Ionosphere

Abstract

MESSRS. FARMER and Ratcliffe¹ criticise my results on this subject² on the ground that I have neglected the effect of a possible variation of the E layer attenuation during the three-quarters of an hour or so in which the observations were taken. Such a variation of E layer attenuation would involve a spurious contribution to the slope of the log , P curve, which would invalidate the calculation of the collision frequency. But where the reflection coefficient decreases to a minimum and rises again (as in all cases observed), there are two branches to the log , P curve, one corresponding to decreasing and the other to increasing, and the effect of a continuous variation of E layer attenuation would be to increase the slope of one branch and decrease that of the other by the same amount. The effect of the variation of E layer attenuation is therefore automatically eliminated in taking the mean of the slopes of the two branches.