On the Origin of Solar Radio Noise

Abstract

The observed anomalous radio-frequency radiations from the sun are associated with sun spot activity and are believed to be generated within intermingling streams of charged particles issuing from active areas of the sun. Such streams have the property of greatly amplifying initial spacecharge fluctuations over a range of frequencies determined by the density and velocity distribution of particles in the stream. The theory of generation of radio energy resulting from space-charge interaction between streams of charged particles is reviewed and applied to the solution of the solar radio noise problem. From estimates of average density and velocity distribution of solar particles the frequency of the most intense radiation (30 to 60 megacycles) and the absolute value of radiation intensity at the surface of the earth (7 to 2)XlO _22 (watt/cm 2 /cycle/sec.) are computed and found to agree well with measurements. The most probable spectral distribution of the anomalous solar radiation is derived in the formwhere E m is the maximum intensity corresponding to the wave-length X m .

Growing Electromagnetic Waves

“…The mechanism has been discussed for simple space-charge electric waves. 2 (4) Ion drifts should not be postulated without considering the secondary effects of the associated electric currents and electrical and mechanical fields of force. A THEORY of "growing" electric space-charge waves in drifting, interpenetrating electron streams, or mixed ion and electron streams, has been developed by Haeff, 1-3 Pierce, 4-6 Nergaard, 7 Bohm and Gross, 8 Feinstein and Sen, 9 Rydbeck and Forsgren, 10 and others.…”

“…The nature of the two pairs is found by considering the limiting case X->0 when the dispersion equation for real radio waves should reduce to c 2 L 2 /u> 2 = 1. The upper sign before the square brackets yields c 2 L 2 /o> 2 =c 2 /V 2 (l-Y) 2 (called El waves) and the lower sign c 2 L 2 /co 2 =l (called E2 waves). The latter are real waves but these do not grow; in the region where L is complex, L r and Li are of opposite sign so that the waves are traveling evanescent waves.…”

“…The actual mechanism of growth is not certain, however, the generally accepted theory having been recently criticized. 2 The discovery of a growth mechanism for (transverse) electromagnetic waves might be of considerable importance. It might permit the design of electronic devices capable fo directly amplifying radio waves.…”

Les émissions radioélectriques d'origine galactique ou extragalactique

“…Le rayonnement galactique général, historique bref, premières théories. -Les premières observations du bruit radioélectrique d'origine galactique remarqué par Jansky en 1932, ont été effectuées sur des fréquences s'étendant de 9,5 à 162 Mc/s (Jansky, 2,0,6 Mc/s; Friis et Feldman, 9,5, 18,6 et 31 Mc/s; Reber, 162 Mc/s).…”

“…celle de Swann : conversion de l'énergie par induction lors de la variation du flux produit par la variation de surface des taches émissives; -celle de Babcook [5] : étoile à champ magné-_ tique intense (10 gauss); -celle de Haefl [6] : rotation différentielle de couches polaires et équatoriales.…”