太阳纯电子事件和质子—电子事件的电子能谱的机制

本文计算、分析了太阳耀斑加速电子在日冕中传输时激发的等离子体尾场的效应,认为耀斑电子的高能成份激发的尾场,能够加速低能耀斑电子,低能耀斑电子的能量增值可达几十keV至上百keV,这种尾场加速将软化约100keV以下的能量范围内(探测阈之上)的耀斑电子能谱。结合考虑尾场效应,本文提出了太阳耀斑加速电子从加速区到形成电子事件之间的能谱演化模式,说明了太阳纯电子事件的双幂律电子能谱和太阳质子-电子事件的单幂律电子能谱的形成,认为两类事件的电子能谱差异为耀斑电子日冕传输中不同程度的尾场效应所致,前者尾场效应弱,电子能谱呈双幂律,后者尾场效应较强,电子能谱为单幂律谱。

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.