| dc.description.abstract | Solar energetic particles (SEPs) are accelerated by solar eruption, e.g., solar flare, cor-onal mass ejection (CME), and plasma jet, or by interplanetary structures, e.g., interplanetary shock (IP shock) and corotating interaction region (CIR). In this study, we would like to char-acterize the light curve of energetic proton flux and spectral parameters, and to find out the associations with shocks and magnetic reconnections by combining the proton flux data with the in situ solar wind data and extreme ultraviolet (EUV) images from Solar Terrestrial Rela-tions Observatory (STEREO) satellite.
We classify the solar proton events (SPEs) observed by STEREO from 2011 to 2014 into five types, including (1) single magnetic reconnection acceleration, (2) multiple mag-netic reconnection acceleration, (3) multiple shock acceleration, (4) magnetic reconnection and shock acceleration, and (5) interplanetary compression region. Our result shows that high-energy (>1 MeV) proton flux increase obviously about an hour after magnetic reconnec-tion occured. Moreover, proton fluxes at higher energies start to increase, reach the peak, and back to the background value earlier than those at low energies. High-energy protons have more obvious response to the magnetic reconnection acceleration than low-energy (<1 MeV). Three following response are seen in the proton light curves when an IP shock passing through the satellite, i.e., (a) flux increase in all energies, (b) flux increase in low-energy pro-tons, and (c) no flux changes. Low-energy protons have more obvious response to the IP shock acceleration than high-energy protons.
In addition, we analyze spectral parameters in all SPEs using the gamma ray fitting function providing by Band et al. (1993). Our results show that the events accelerated by sin-gle and multiple magnetic reconnection have smaller power law index at high energies but no preference is found at low energies. The multiple shock acceleration events have larger power law index at low energies but no preference at high energies. It is suggested that protons can be accelerated to a few tens of MeV or even a few hundreds of MeV by magnetic reconnec-tion. The ??? (energy break) for the events of magnetic reconnection and then shock accelera-tion is found to be in the range of 8-40 MeV. | en_US |