Extreme solar particle events shown in carbon-14 data

Abstract:

Cosmogenic nuclides in natural archives, i.e., ¹⁴C in tree rings, and ¹⁰Be, and ³⁶Cl in ice cores, are a good proxy of past extreme solar particle events. Among them, ¹⁴C is more advantageous since a ¹⁴C concentration in a tree specimen shows ¹⁴C values representative of the whole troposphere and we can search for past extreme solar events by using only a single wood sample.

We have searched for past extreme events by measuring ¹⁴C concentrations in tree rings continuously with annual resolution. In this presentation, the progress of the past event search and the occurrence rate of extreme solar event will be reported.