DETECTION OF A SOLAR PARTICLE EVENT AT AN HELIOLATITUDE OF 73.8-DEGREES-S

We report the observations of an electron event at a heliolatitude of 73.8 degrees S, the highest latitude interplanetary solar event reported to date. This event was detectable because the interplanetary background was not obscured by electrons produced in co- rotating interaction regions. The event was associated with an interplanetary type III burst and a solar active region located at 6 degrees S as detected by the Nancay radioheliograph. The origin of the electrons is discussed. The observations favor an acceleration process in the low or middle corona followed by coronal propagation from the solar source to the highest heliolatitudes. This high latitude electron event presents rather different characteristics from those detected at low heliolatitudes.