Separation and Analysis of Temporal and Spatial Variations in the 10 April 1969 Solar Flare Particle Event

Abstract

We analysed the 10 April 1969 energetic particle event with five spacecraft separated over 180° in azimuth. The particle fluxes are mapped back to the coronal injection longitudes which are estimated from the instantaneous solar wind velocities and connected at the same time of observation to give the longitudinal particle gradients. Cutting these gradients at representative longitudes gives the temporal variations at fixed coronal longitudes which turn out to be power-law decays. This shows that the exponential rise and decay observed by spacecraft is due to the spatial gradient sampled by the spacecraft as the connection longitude changes due to the Sun’s rotation.