The solar elongation distribution of low-frequency radio bursts

Over 500 days of low-frequency (<1 MHz) radio observations from the IMP-6 spacecraft have been accumulated to produce a two-dimensional map (frequency vs elongation) of solar type III bursts occurrences. This map indicated that most solar bursts in this frequency range are observed at the second harmonic of the plasma frequency rather than the fundamental. The map also shows that the solar wind electron density varies as Rsup(-γ), where γ can be somewhat less than 2 to perhaps 3 or higher. (Auth.)