(14.7.2017) “It is almost certainly SAMA,” Oliva said, using an acronym for the South Atlantic Magnetic Anomaly. This weakness in Earth’s magnetic field, centered over South America and the South Atlantic, allows one of Earth’s Van Allen radiation belts—zones of energetic particles trapped by the magnetic field—to dip closer to the atmosphere. As a result, much of South America and part of the South Atlantic Ocean get an extra dose of radiation.