AN EXPLANATION TO THE ELECTRON ENERGY SPECTRA OF SOLAR PURE ELECTRON EVENTS AND PROTON-ELECTRON EVENTS

The plasma wake fields (PWF) excited in background plasma by solar flare electrons during their coronal propagation are calculated and an effect PWF is analysed in this paper.It is shown that the PWF excited by high-energy solar flare electrons could accelerate low-energy flare electrons and increase their energies by tens or hundreds keV,and,due to this acceleration,the flare electrons’ energy spectrum below about 100 keV could be softened.Considering the PWF effect and other processes,the paper suggest a model for the evolution of energy spectrum of solar flare electrons from acceleration region at the Sun to about 1 AU.It is concluded that,for a solar pure electron event,for which the PWF effect is weak,the electron energy spectrum fits to a double power law,and for a proton-electron event,the PWF effect is strong and the spectrum exhibits a single power law.