Variations in Radiocarbon Production in the Earth's Atmosphere

Abstract

We have investigated solar phenomena associated with unusual changes in the production rates of 14C in the atmosphere. 14C is produced in interactions of cosmic ray neutrons with nitrogen in the atmosphere. Intensity of the neutrons varies globally and fluctuates with time as a result of interactions of galactic cosmic rays which generate neutrons with plasma and magnetic fields of the solar wind. We estimate the total mean production rate of 14C for solar cycle 20, specifically 1965 to 1975, to be 2.25 ± 0.1 nuclei-cm−2sec−1 from galactic cosmic rays alone, with negligible integrated contribution from solar particle events. Annual averages of Rz, the Zurich sunspot number, and the production rate of 14C, n(14C), were related by n(14C) = 2.60–5.53 × 10–3 Rz ± 3 percent. The contribution of solar flare particles and the zero sunspot limit are discussed with relation to major fluctuations that appear in the radiocarbon versus dendrochronology over short (∼100 years) integration times.

The Worldwide Marine Radiocarbon Reservoir Effect: Definitions, Mechanisms, and Prospects

“…The solar magnetic field also affects the trajectories of charged particles travelling through our solar system. It acts as a shield, inhibiting primary cosmic radiation from penetrating the Earth's atmosphere, playing an important role in the production of cosmogenic nuclides (Gosse & Phillips, 2001;Korff & Mendell, 1980;Muzikar et al, 2003;Stuiver et al, 1997). Stuiver (1961) was the first to observe that variations in radiocarbon Reviews of Geophysics 10.1002/2017RG000588 production rates are caused by solar wind modulating the interplanetary magnetic field.…”

“…Stuiver (1961) was the first to observe that variations in radiocarbon Reviews of Geophysics 10.1002/2017RG000588 production rates are caused by solar wind modulating the interplanetary magnetic field. Sunspots have a higher magnetic field than the average field that is displayed by the Sun (Korff & Mendell, 1980;Tobias et al, 2004) and are a useful index for solar activity (Masuda et al, 2009). These features have been observed over the past several centuries, and the number of spots is inversely correlated with radiocarbon production rates (Masuda et al, 2009).…”

Theoretical Establishment of the Mass Balance Equation and Determination of the Proportion (<i>S</i>)<i><sub>ff</sub></i> of Fossil Fuels as an Indicator of the Suess Effect

“…As a result, they react with the atomic nuclei of the air, present in the atmosphere and troposphere, to form carbon-14. The production of C14 is brought about by the capture of neutrons by nitrogen (80% in the atmosphere according to [6] is by far the most frequent reaction 14 N (n, p) 14 C [7].…”

Sun, Ocean, Nuclear Bombs, and Fossil Fuels: Radiocarbon Variations and Implications for High-Resolution Dating

“…Radioactive 14 C decays to 14 N through beta decay, with the formation of antineutrinos and a decay half-life of 5,730 ± 40 years (Godwin 1962): 14 C 6 → 14 N 7 + e − 1 + ν e . Korff & Mendell (1980) estimated that the global average rate of production of 14 C in the atmosphere is approximately 2.2 atoms cm −2 s −1 , about 90% of which are from galactic cosmic rays and the remaining 10% are from solar cosmic rays (Damon & Sternberg 1989). A recent estimate of the global production rate of 14 C, based on carbon cycle models, is 1.7 atoms cm −2 s −1 (Roth & Joos 2013).…”