Solar Energetic Electron Spectra with a Bump-like Break

The energy spectrum of solar energetic electrons carries crucial information on the origin/acceleration of energetic electrons at the Sun. Here we present a study of eight solar energetic electron events with a bump-like spectral break, observed by the WIND 3D Plasma and Energetic Particle instrument at energies from ~1 keV to >100 keV. After considering the uncertainties in both the electron flux and energy, we fit the background-subtracted electron peak flux versus energy spectrum well to three functions: the sum of a single-power-law and a Gaussian function, the product of a single-power-law and a Gaussian function, and a triple-power-law function. For the sum of a single-power-law and a Gaussian function, on average, the fitted spectral index is 2.8±0.1, and the fitted break energy is 21±4 keV with a transition energy range of 32±22 keV. For the product of a single-power-law and a Gaussian function, the fitted spectral index is 2.7±0.9, and the fitted break energy is 97±58 keV with a transition energy range of 193±74 keV. For a triple-power-law function, the fitted spectral index is 2.7±0.1 at energies below an upward break energy Eb1 of 11±2 keV, is 1.7±0.1 at energies between Eb1 and a secondary downward break energy Eb2 of 89±13 keV, and is 3.5±0.3 at energies above Eb2. Finally, we will present the association of energetic electron spectra with other solar phenomena such as SXR flares, HXR flares, CMEs, radio bursts, etc., in order to investigate the origin/acceleration of solar energetic electrons in these events.