Stefano De Santis Cosmic Days
LINK ===== https://urluss.com/2tlyoV
Recently, the AMS collaboration Aguilar (2021a) reported periodicities of 27-days, 13.5 days and 9 days in the daily proton fluxes measured by AMS in the period of time from May 2011 to the end of October 2019. As first observed in 1938, recurrent variations with a period of 27 days, corresponding to the synodic solar rotation and at multiple of that frequency (e.g. periods of 13.5 and 9 days) are related to the passage of corotating interaction regions originating from one or more coronal holes of the Sun (Modzelewska and Gil 2021). Until the AMS measurements the general idea was that the strength of the periodicity steadily decreases with increasing rigidity of cosmic rays, differently in solar maximum and minimum (Gil and Alania 2013). AMS measured a 27-day significant periodicity with 95% confident level only from 2014 to 2018 with a rigidity dependence significant up to 20 GV that varies in different time intervals. The 9-day and 13.5-day periodicities are visible in 2016, their strength unexpectedly increases with increasing rigidity up to \\(\\approx10\\text{GV}\\) and \\(\\approx20\\text{GV}\\) respectively, and then decreases with increasing rigidities. 59ce067264