Oblique-incidence radio transmission and the Lorentz polarization term

The force on an electron in an ionized medium may be written 6"+47raP per unit charge, where 6" is the electric force, P the polarization of the medium, and a a constant which is zero on the Sellmeyer theory and may have a value of 1/3 on the Lorentz theory. A well-defined distinction exists between maximum usable frequencies for ionospheric radio transmission calculated on the basis of the two theories. This paper describes a type of experiment for measuring maximum usable frequencies and comparing them with calculated values. The results indicate that a is probably zero, at least in these experiments. There is a lsu described a stlip-by-step method of solving the virtual-height integral equation, necessary in much theoretical work concerning the ionosphere.