GEOMAGNETIC FOCUSING OF COSMIC RAYS IN THE LOWER ATMOSPHERE - EVIDENCE AND MECHANISM

This paper shows that geomagnetic rigidity and the elevation of measurement point could not explain the irregularities found in the spatial distribution of annual mean cosmic ray radiation, detected by neutron monitors (NMs) spread over the world. Our theoretical analysis reveals that longitudinal gradient of heterogeneously distributed geomagnetic field could focus the extended showers of energetic particles in some regions of the Earth. We show that in regions with a positive, steeper rising cross-longitudinal magnetic gradient the NMs detect a higher annual mean radiation dose, compared to regions with a zero, or a negative magnetic gradient. Moreover, we found out that the shape of the NMs' seasonal variations is confined to geographic latitude, and covariate fairly well with the lower stratospheric ozone (O-3), with an opposite phase. We hypothesise that this connectivity could be attributed to the ozone modulation of the mean free path of the cosmic rays' nuclei in the atmosphere and the muons production in the lower stratosphere.