Open Access

Table 1.

The months of start and end, as well as the values of minimum and maximum solar activity expressed in terms of F 10.7, are shown for each of the solar cycles 21, 22 and 23. The solar cycle 24, which is not practically considered in this study, is included for completeness.

Solar cycle Initial month–final month Minimum F 10.7–maximum F 10.7 (10−22 Wm−2 Hz−1)
21 June 1976–September 1986 72.7–207.5
22 September 1986–May 1996 72.8–201.4
23 May 1996–December 2008 69.6–164.7
24 December 2008– 64.9–

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.