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

Solar Storms Forecast Study of Stinspot Activities Reveals Facts That Aid Communications Engineers in Handling Radiotelegraph Traffic During Magnetic Disturbances. MAGNETIC storms originating from siuispots now can be forecast over short periods depend- ably to within fifteen minutes of the start of their destructive effects on world-wide radio communica- tions, research engineers of the Radio Corporation of America have discovered. Forecasting with such accuracy becomes possible because of a bet- ter understanding of solar disturb- ances, the RCA engineers told an international gathering of scien- tists recently in Washington. They disclosed the results of observa- tions and studies which may shake many time-worn concepts. Their investigations proved that the size of sunspots is "a meaning- less criterion" in predicting havoc that may be caused to radio circuits. Composition of the spots, their polarity and their position on the face of the sun were declared to be the determining factors of lethal bombardment. Moreover, the RCA investigations established the existence of a "cri- tical zone" on the face of the sun— an area about 26° in radius from the optical center of the sun, on its eastern herisphere. It was discov- ered that the position of sunspots in relation to this critical zone was of utmost importance. Damaging effects on world radio communica- tions occur when they are within this zone. Sun May Have Ionosphere "The existence of a critical zone on the sun," the RCA engineers said, "poses an interesting specula- tion with regard to the existence of a solar ionosphere, or the equivalent thereof, corresponding to the layer of ionized gas surrounding the earth. This might be the corona or the prominences overlying sun- spots. If the 26° semi-circle delin- eates a region from which radia- tions affecting the earth's iono- sphere are confined, these radia- tions penetrate the solar ionosphere, only when about seven minutes of arc of the line connecting the sun and the earth. Sunspot radiations of lower angle do not reach the earth, or are returned to the sun." These new facts on solar disturb- ances—which cause worldwide radio communications and broadcasting companies considerable concern— were presented by H. E. Hallborg and Miss Audrey Arzinger, of RCA Laboratories, Princeton, N. J., and J. H. Nelson, of RCA Communica- tions, Inc., before a joint session of the Institute of Radio Engineers and the International Scientific Radio Union in Washington on May 3. Taking account of the fact that sunspots have been observed for more than 150 years, and that vol- umes have been written about them, the RCA engineers stated that their investigations represented no in- vasion into the field of the astro- nomer, but rather an effort to co- operate with him in the application of solar knowledge. "We have established that mere size of a sunspot is a meaningless criterion in assessing its possible damage to communications," the re- port stated. "A huge spot, consist- ing mostly of penumbra, or dark fringe, may be a complete dud in its effect upon radio circuits. A small spot mostly umbra, or inner darkness, may be quite deadly. Rapidly changing spots, indicative of activity, are the most lethal in their effects upon radio circuits." Observatory Supplied Reports The RCA scientists accredited the Mount Wilson Observatory with providing regular reports on the polarity of the umbras as red (posi- tive) and violet (negative), to- gether with i-elative intensities of the red and violet. It was found that the reds have a prepondei'ant effect in the northern hemisphere of the world, violet in the southern hemisphere. Reds were said to de- press frequencies in the northern hemisphere and raise them in the southern. The action of the violet was discovered to be vice-versa. "This phenomenon," the RCA en- gineers said, "may be due to the earth's polar attraction for solar radiations of opposite polarity, NELSON SWINGS AN 8-FOOT TELESCOPE T(i\\ 4RD THE SUN FOR STUDY OF THE EVER-CHANGIN(, fe'lL-kn .iPOTS. [8 RADIO AGE]