HR: 0800h
AN: SH31B-06    [Abstracts]
TI: Characteristics of Solar Proton Events Associated with Cosmic Ray Ground Level Enhancements
AU: * Oh, S
EM: osy1999@cnu.ac.kr
AF: Bartol Research Institute, 217 Sharp Lab, Department of Physics and Astronomy, University of Delaware, Newark, DE 19716, United States
AU: * Oh, S
EM: osy1999@cnu.ac.kr
AF: Chungnam National University, 220 Gung-dong, Yuseong-gu, Dajeon, 305-764, Korea, Republic of
AU: Yi, Y
EM: euyiyu@cnu.ac.kr
AF: Chungnam National University, 220 Gung-dong, Yuseong-gu, Dajeon, 305-764, Korea, Republic of
AU: Bieber, J
EM: john@bartol.udel.edu
AF: Bartol Research Institute, 217 Sharp Lab, Department of Physics and Astronomy, University of Delaware, Newark, DE 19716, United States
AU: Evenson, P
EM: evenson@udel.edu
AF: Bartol Research Institute, 217 Sharp Lab, Department of Physics and Astronomy, University of Delaware, Newark, DE 19716, United States
AB: Previous studies on Solar Proton Events (SPEs) used the definition that a SPE is an event with more than 10 pfu (Particle Flux Unit; 1 particle cm^-2 sr^-1 s^-1) for the peak fluxes of > 10 MeV integral intensity of protons. Even though SPEs are major events with great peak intensity, they do not have a one-to- one association with Ground Level Enhancement (GLEs). On the contrary, minor SPEs are associated with GLEs sometimes. To investigate this puzzle, we examined the peak intensities of 83 SPEs after 1986 using the intensity of proton energy channels (P6-P11) (not integral intensity) from GOES. SPEs associated with GLE comprise 31 events and have well-defined profiles with large increase and clear peak for each proton channel. They have larger peak intensity, fluence, and shorter delay time between onset and peak than SPEs without GLE. Fluence and peak intensities of SPEs have a good correlation with percent increases of GLE, with the best correlation coefficients obtained for the peak intensities of P8, P9, and P10. For these energy channels (spanning 350-700 MeV), we find that there are critical threshold values for GOES fluence and peak intensity. Most SPEs above the thresholds are associated with GLE, while almost none below the thresholds is not.
DE: 2101 Coronal mass ejections (7513)
DE: 2104 Cosmic rays
DE: 2114 Energetic particles (7514)
DE: 2164 Solar wind plasma
DE: 7519 Flares
SC: SPA: Solar and Heliospheric Physics [SH]
MN: 2009 Joint Assembly