RESEARCH ON SUNSPOTS

Press, Volume C, Issue 29620, 16 September 1961, Page 16

RESEARCH ON SUNSPOTS

Mr C. H. Cummack's Discovery Certain features of the ionised “F-layer” of the atmosphere—the layer, about 90 to 200 miles up, off which long-distance short-wave radio transmissions are bounced —have puzzled geophysicists ever since measurements were first made on the layer by ionosonde. One phenomenon difficult to explain is the effect of the average (“smoothed") number of sunspots over different stages in the sunspot cycle. Up to a certain stage a greater number of sunspots means a greater usable radio frequency; but beyond this point the effect begins to taper off. Mr C. H. Cummack, of the Geophysical Observatory, has now made a mathematical analysis which gives an explanation of the shape of the curve. The solution may be important for short-wave radio propagation and in satellite problems. Mr Cummack’s solution explains the phenomenon in terms of a “heat sink" about 80 miles up. from which heat is probably lost by infra-red emission from atomic oxygen. The suggestion that there might be a heat sink, and its probable cause, had been made by Professor D. R Bates, of Queen's University. Belfast, but this is the first demonstration of its existence.