Evidences of high energy protons with energies beyond 0.4 GeV in the solar particle spectrum as responsible for the cosmic rays solar diurnal anisotropy

摘要

Analysis on the daily variations of cosmic ray muons with $E_{\mu}\geq 0.2GeV$ based on the data of two directional muon telescopes at sea level and witha rigidity of response to cosmic proton spectrum above 0.4 GV is presented. Theanalysis covers two months of observations and in 60% of days, abrupttransitions between a low to a high muon intensity and vice-verse is observed,the period of high muon intensity is from $\sim 8.0h$ up to $\sim 19.0h$ (localtime) and coincides with the period when the interplanetary magnetic field(IMF) lines overtake the Earth. This behavior strongly suggest that the highmuon intensity is due to a contribution of solar protons (ions) on the muonintensity produced by the galactic cosmic rays, responsible for the low muonintensity. This implies that the solar particle spectrum extends to energiesbeyond 1 GeV. We show that this picture can explain the solar daily variationorigin, and it is a most accurate scenario than the assumption of corotatinggalactic cosmic ray with the IMF lines, specially in the high rigidity region.Obtained results are consistent with the data reported in others papers. Someaspects on the sensitivity of our muon telescopes are also presented.