Generation of solar type III bursts at the second harmonic

Using the data from our experiments on the IMP-6 (Explorer 43) satellite, we have examined over 200 type III bursts at kilometric wavelengths, including 16 bursts which were accompanied by >18 keV electron events with sharp onsets, in a search for the electrostatic waves which, according to theory, should be the primary source of type III bursts. No electrostatic waves of sufficient intensity to generate the type III bursts by any of the wave-wave scattering theories which produce the second harmonic of the plasma frequency, have been found.