Volume 16 (1938) Issue 11 Pages 421-430
Recently, Dellinger's phenomena which make the transmission of short waves impossible, attract the attentions of those who are engaged in the wireless-communication or in the observation of the earth's magnetic field and many studies have been made in the ionospheric conditions and magnetic and electric fields. The author investigated the magnetic field of the phenomena occurred during 1935-36, and found that the disturbance in the ionosphere not far from Japan causes the magnetic changes (De) so as to increase the amplitude of the diurnal variation. On comparatively quiet days, we obtained 0.2-0.9 for the ratio De/Ω0, where Ω0 is the departure from the preceding and following midnight.
The author calc_??_lated the magnetic potential of the disturbing field by the increase of electrons in the ionosphere. When the increase is constant in the area Se, where σ0+σs and σ0 are the total conductivities when the ionosphere is disturbed and when it is not disturbed respectively, where [φ0]m is the mean normal current function in Se, α the ratio of current in the external and internal portions (Si) induced in the earth-core, and ωe or ωi are the solid angles subtended by Se and Si respectively. From these studies we see that the dynamo-theory is appropriate for interpreting De and the drift current and diamagnetic theories are not, since De is always produced in the sense to decrease the permanent field in the latter theories