Production of 7Be Nuclei in the Earth's Upper Atmosphere from Galactic Cosmic Rays and Solar Energetic Particles
Abstract
Galactic cosmic rays (GCR) produce 7 Be radioactive nuclei from nuclear interactions with the atmospheric N and O nuclei. In addition, extraordinarily intense solar energetic particles (SEP) associated with a great coronal mass ejection (CME) event contribute to production of 7 Be nuclei, though a frequency of such solar proton event is very low and its duration is less than a few days. The SEP proton spectrum is so steep that most of 7 Be is produced in a thin top layer of the polar atmosphere. We calculate the global average 7 Be production rate in the upper atmosphere taking account both GCR and SEP protons. The production rate of 7 Be by the intense SEP event increases about a few tens times that by GCR. We compare the present calculation with the measurement of 7 Be and discuss the SEP effect to 7 Be production.
- Publication:
-
International Cosmic Ray Conference
- Pub Date:
- July 2003
- Bibcode:
- 2003ICRC....7.4273Y