Occurrence Probability of Large Solar Energetic Particle Events: Assessment from Data on Cosmogenic Radionuclides in Lunar Rocks
Abstract
We revisited assessments of the occurrence probability distribution of large events in solar energetic particles (SEP), based on measurements of cosmogenic radionuclides in lunar rocks. We present a combined cumulative occurrence probability distribution of SEP events based on three timescales: directly measured SEP fluences for the past 60 years; estimates based on the terrestrial cosmogenic radionuclides 10Be and 14C for the multi-millennial (Holocene) timescale; and cosmogenic radionuclides measured in lunar rocks on a timescale of up to 1 Myr. These three timescales yield a consistent distribution. The data suggest a strong roll-over of the occurrence probability, so that SEP events with a proton fluence with energy > 30 MeV greater than 1011 (protons cm−2 yr−1) are not expected on a Myr timescale.
- Publication:
-
Solar Physics
- Pub Date:
- January 2014
- DOI:
- 10.1007/s11207-013-0333-5
- arXiv:
- arXiv:1305.5088
- Bibcode:
- 2014SoPh..289..211K
- Keywords:
-
- Cosmic rays;
- solar;
- Flares;
- energetic particles;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- Solar Physics, in press