A quick method for analysing ionospheric records

A method is described by which routine (h′ - f) records can be analysed quickly to give information about the vertical distribution of electron density in the ionosphere. The method is approximate but is simple and quick to use, and is therefore convenient for making analyses of the type required for testing theories of the ionosphere. It consists in assuming, after Appleton, that the electron distribution is parabolic and then in constructing a series of curves, similar to those of Booker and Seaton, on a transparent scale, in such a way that they can be matched directly to the photographic records. The important parameters can then be read directly from the scale. Retardation in the F1 layer can be allowed for when the F2 layer is being analysed. Scales based on other electron distributions are also described and are useful in the analysis of unusual records of the type sometimes encountered at Huancayo. An account is given of the calculation of the total number of electrons in a unit column of the F2 layer below the level of the maximum. The calculations are made on the assumption that the earth's magnetic field is zero, and the effect of removing this limitation is discussed.