An Investigation of the Speed of the Solar Disturbances Responsible for Type III Radio Bursts

The paper describes an investigation aimed at finding out whether solar radio bursts of spectral type III are due to disturbances which travel out through the corona with velocities exceeding O·lc, as predicted by the well-known hypothesis that the emissions are due to plasma oscillations. If the proposition is correct, emissions at different frequencies would be generated at different levels in the corona-the lower the frequency the higher the source. This property is tested by simultaneous directional observations at a number of frequencies between 40 and 70 Mc/s, using a swept-frequency interferometer.