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 space-charge 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)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}22}$ (watt/${\mathrm{cm}}^{2}$/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 form $\frac{E}{{E}_{m}={(\frac{\ensuremath{\lambda}}{{\ensuremath{\lambda}}_{m}})}^{2}}\mathrm{exp}{2[1\ensuremath{-}(\frac{\ensuremath{\lambda}}{{\ensuremath{\lambda}}_{m}})]}$where ${E}_{m}$ is the maximum intensity corresponding to the wave-length ${\ensuremath{\lambda}}_{m}$.