Effects of the South Atlantic Anomaly on the muon flux at sea level
  The goal of this study is to examine the response and changes of the muon intensity at ground, due to magnetic anomaly over south Atlantic. Based on the data of two directional muon telescopes and located at 22S and 43W. These coordinates are inside of the South Atlantic Anomaly (SAA) region, a dip in the magnetosphere. This characteristic offers to the muon telescopes the lowest rigidity of response to cosmic protons and ions ($\geq 0.4$ GV). The magnetosphere's dip is responsible for several processes, such as the high conductivity of the atmospheric layers due to the precipitation of energetic particles in this region and an zonal electric field known as the pre-reversal electric field (PRE) with an enhancement at evening hours. In addition the open magnetosphere, propitiate the magnetic reconnections of the IMF lines that will take place in this site in the day side. These factors are responsible for an unusually large particle flux present in the SAA region, including particles with energies above the pion production threshold. The main effect is an increase of the muon intensity ($E_{\mu}>0.2GeV$) at ground, in the day side, in up to ten times. We show that it is correlated with the pre-reversal electric field, and propitiate the observation of muon enhancements due to small solar transient events, such as corotating interaction region (CIR) and micro-flares. Details of these results are reported in this paper. 
C. R. A. Augusto, J. B. Dolival, C. E. Navia, and K. H. Tsui