Ray-path characteristics in the ionosphere

The paper is based on an earlier one by the author1 and presents an improved method of making magneto-ionic calculations that is both quicker and more accurate than the graphical construction previously given. By means of a new parameter the symmetrical cases can be studied in a simple manner and the asymmetry in the general case can be more readily examined. Propagation in the magnetic meridian plane is discussed in detail, including the phenomenon described by Poeverlein of a cusp at the apex to the ray path within a certain critical angle of incidence. The problem of direction-finding errors at short distances due to the lateral deviation caused by the earth´s magnetic field is treated as a perturbation of the vertical incidence case, and it is shown that the effect is likely to be large only under critical conditions that it would be difficult to obtain in practice. The paper ends with a short discussion of absorption, with special reference to the effect of the earth´s magnetic field on non-deviative absorption.