Experimental studies of the motions of slow electrons in air with application to the ionosphere

Abstract

From careful experiments on the motions of slow electrons in air, it has been possible to deduce empirical formulae from which may be derived the drift velocity, collisional frequency, electronic temperature and mean energy loss per collision. These results applied to the ionosphere allow electronic collisional frequencies to be readily found in the ionosphere below 94 km, from the pressure of the air alone. It is considered that the values of the collisional frequencies found in this manner are more trustworthy than any that have been suggested hitherto. The accuracy is limited by the accuracy of the data on pressure found by other means. The collisional cross-sections of the molecules of air and nitrogen when the electronic temperature is less than about 2600° K has been found to be directly proportional to the speed of the electron.