A Discussion of Radio Wavelength Radiation Generated by Gyrosynchrotron and Langmuir-wave Processes

Abstract

Synchrotron and Langmuir-wave emission processes are compared, with special emphasis being placed on metre wavelength radiation from the solar corona. Numerical calculations are presented which relate to brightness temperature, circular polarization and source structure. It is found that both gyrosynchrotron and Langmuir processes can produce brightness temperatures up to ~ 2-3 GK; larger temperatures require induced Langmuir-wave emission. It is further shown that gyrosynchrotron source positions observed at different frequencies may have a dispersion in height within an inhomogeneous background medium. Although many observations may be explained excIusivelyby. one of the two processes, there are numerous circumstances in which both processes are equally likely.