Solar Activity from the Mid-Second Millennium B.C. to the First Millennium A.D. Based on Radiocarbon Data

The paper reports the results of reconstruction of the heliospheric modulation potential from radiocarbon data for the time interval from the mid-second millennium B.C. to the end of the first millennium A.D. It is known that significant climatic changes took place on the Earth during that time; specifically, the thickness of glaciers in Iceland and Norway were changing. Coincident changes are also observed in the radiocarbon data. The results of calculations show that the heliospheric modulation potential reaches a maximum (~590 MV) on this interval approximately in 1705 B.C. This suggests that solar activity at that moment was highest for the considered interval. Conversely, around 750 and 350 B.C., the smallest values of the modulation potential were observed and, consequently, solar activity could be lowest from the mid-second millennium B.C. to the end of the first millennium A.D.