Geomagnetic-Heliomagnetic Modulation of Atmospheric Radiocarbon Production

• Published in: Radiocarbon
• Main Authors: Damon, Paul E, Linick, Timothy W
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1986
• Subjects: ice core; North Magnetic Pole
• Online Access: https://doi.org/10.1017/s0033822200007360; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033822200007360

New Arizona high precision Δ 14 C data back to 6500 BC plot close to an 11,300-yr period sinusoid extrapolated from the post 5300 BC data (offset = +32‰, half amplitude = 51‰ and phase lag = 2.29 radians). The trend curve is modulated by high latitude components of the non-dipole field with a fundamental period of 2400 yr. Based upon a model of Lund and Banerjee (1985), the non-dipole field rotates and every 1200 yr the high latitude maxima pass over the north magnetic pole and near the south magnetic pole in reversed polarity. This modulates cosmic ray production producing extended maxima ca AD 1700, 700 bc, 3100 bc, and 5500 bc. The 2400 period appears to be stationary. The magnetic field also modulates the amplitude of the solar activity induced cycles of periods 200, 80, and 11 yr as can be seen in the Zürich-Bern Camp Century ice core data as well as in the Δ 14 C fluctuation data. Reinterpretation of the Camp Century 10 Be data indicates that it is in agreement with magnetic field as well as solar activity modulation of terrestrial radioisotope production.