Critical-Frequency Difference Variations and the Poynting Vector in the Ionosphere

Abstract

MEASUREMENTS of the F₂-layer critical-frequency difference, f^x – f⁰, have now been made for the hourly records taken at Churchill, Manitoba, in 1945 and 1946 and at Portage la Prairie, Manitoba, in 1947 and 1948. These measurements corroborate results¹ already reported for Clyde River, Baffin Land, in that large diurnal variations in the apparent magnetic field are found. However, the calculation assumes that ordinary and extraordinary modes are reflected from the same region of the ionosphere.