Type III bursts traced from the solar surface to 1 AU

Abstract

We trace type III radio bursts from the sun until they can be observed as in situ electrons at the ISEE-3 spacecraft. Our study extends over the period of operation of the electron experiment on ISEE-3 from August 1978 to November 1979. Our observations include data from solar flares, kilometric type III burst spectra from ISEE-3, and in situ measurements of low energy electrons from ISEE-3. By carefully restricting the data sets involved, we find a peak of 20° width in the number of flares associated with in situ electrons near 60° west solar longitude. This peak shows that the electron beams of type III bursts are not spread over a great range of longitudes as earlier studies indicate, but are fairly limited in spatial extent. However, even in that longitude range only 40% of type III-flare events are associated with in situ electrons.