Solar-terrestrial disturbances of June-September 1982, 4

In so far as a solar x-ray flare regarded as a spearhead of solar-terrestrial electromagnetic disturbances was concerned, some of the events occurred from June to September, 1982, were comparable to the events which had occurred in August, 1972, in their hugeness, but did not exceed the latter. The largest event occurred on July 9, and its enhanced flux (0.1 - 0.8 nm) was 0.98 x 10-3 Wm-2 as the maximum value. Both enhanced gaint solar x-ray flare fluxes and the corresponding sudden phase anomalies (SPA) occurred in the circuits of long distance propagating VLF radio waves received at lnubo favorably conformed to the empirical causal relation of both which had been obtained in the past for the selected events. On the basis of this conformity, the physical quantities related to the maximum SPA value were estimated from the relation which had been obtained in the past. Moreover, the height distribution of enhanced electron number density due to photoionizztion was determined as the steady solution, and the various aspects of disturbance were discussed. Finally, the sudden enhancement of atmospherics and geomagnetic solar flare effect were qualitatively treated as transversely and longitudinally detected sudden ionospheric disturbances. (Kako, I.)