The R-F Thermal Radiation from the Sun

Citation

Young, Richard Davidson (1952) The R-F Thermal Radiation from the Sun. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/7084-7319. https://resolver.caltech.edu/CaltechETD:etd-10312008-112710

Abstract

The thermal component of the radio frequency radiation from the sun is derived from the laws of classical physics. With the "velocity distribution" method of the kinetic theory of gas the mean number of collisions per second between the particles is found. From this the absorption coefficient for the radiation is obtained. For the intensity of the emitted radiation the equation of transfer is solved in a three dimensional medium. In the solution the emissivity is eliminated by means of a modified form of Kirchhoff's law of radiation where the index of refraction is generalized to include absorption as well. For the path of the rays the equation of the iconal of geometrical optics is considered in a refracting and absorbing medium. The solution does not exhibit the phenomenon of total reflection, present in purely refracting media. Numerical calculations give the distribution of the radiation across the solar disk from 30 mc through 3000 mc. At 3000 mc the sun is of nearly uniform brightness with a sharply defined limb. At the lower frequencies a small central portion becomes quite bright and the limb less distinct and darker.

Thesis Files