Radio age research, manufacturing, communications, broadcasting, television (1941)

the time of a Dellinger fade and they appear to project enough radiation to account for this phenomenon on the earth. When great magnetic storms occur they follow by two or three days a Dellinger fade, which would suggest that they are the result of a properly directed beam of particles spewed out by the same flare that produced radiation for the Dellinger fade. In addition, both of these ionospheric upsets are more frequent during the peak years of the 23-year sunspot cycle, which is also the time of the greatest number of observed flares. Another Cause Is Sought It would simplify the propagation expert's life if the solar flare could be named the villain of all radio com- munication breakdown, not just the Dellinger fades and great magnetic storms. Unhappily, the flare, according to most theories, can be assigned only a relatively minor role. Flares are short-lived and erratic, while the iono- spheric disturbances that yet elude full explanation — the somewhat regular ones known as M-region disturb- ances — appear to be caused by something that lives for many months on the sun, reappearing several times in rough synchronization with the sun's 27-day rotational period. Gaining support from experts is the hypothesis that the sun's outer atmosphere, the corona, has at all times a number of invisible long arms that sweep out millions of miles into space. Some of these coronal streamers would be aimed, as it were, to intercept the earth in its orbit. Unlike the flare-caused beams of particles, coronal streamers would be semi-permanent projections of the corona, lasting for several cycles of the sun's 27-day rotational period. The Rocky Point trio is working with other solar observers to check the validity of this theory. A goal of Dr. Miller's current studies is to establish beyond a doubt what it is on the sun's surface that can build up the corona to such an extent that a streamer will be cast out into space. The Rocky Point photo- graphs are, as he puts it, "not in disagreement with modern theories of the corona and the formation of streamers." The detailed "full-face" photographs do not reveal the whispy streamers themselves but they do show a generous sprinkling of black dots which have never been "isolated" before. These dots, Dr. Miller explains, are probably a bird's-eye view of solar spicules, a short-lived but common activity of the sun first discovered, on the sun's rim, only 14 years ago. They may well be long narrow jets of heated material from the interior of the sun that pop right through the sun's surface, spewing new matter up into the corona. The research team lines up sun's image on screen before exposing film in the camera plate holder. Left to right are A. B. Moulton, Ralph E. Franklin, and Dr. Miller. Hoiv Stieameis May Be Born Normally, the theory goes, spicules reinforce the corona at a steady rate. But when an above-average number of spicules are clustered in a particular region on the sun, and if, at the same time, there are "favor- able" distortions of the sun's magnetic field in that area, the corona bulges and a streamer is born. That the spicules seen as dots in the Rocky Point photographs are the same things seen as long thin spikes in coronagraphs, has been the subject of considerable checking at Rocky Point. Dr. Miller is now optimistic that this correlation can soon be established: the black dots have roughly the same lifetime (3-4 minutes), the same size (5-6000 miles in diameter, miniscule by solar standards) and the same population density as the spicules seen by others in profile photographs. Riding herd on spicules along with Dr. Miller are A. B. Moulton and Ralph E. Franklin. Both have been engaged in communications and research engineering with RCA for nearly thirty-five years, and both boast years of experience as backyard astronomers. To help in analysis and interpretation of their pic- tures, the Rocky Point trio are receiving the assistance of Dr. Walter Orr Roberts, Dr. Joseph N. Rush, and other solar experts of the High Altitude Observatory of Harvard and Colorado Universiries, at Climax, Colorado, under a contracr with RCA Laboratories. The superla- tive coronagraphic results obtained at Climax are avail- able for continuing comparison with the "full-face" observations of Rocky Point. RAD/O AGE 23