Phys.org  July 2, 2024 The impacts of strong solar particle events (SPEs) would be far more severe when the Earth’s protective geomagnetic field is weak, such as during past geomagnetic excursions or reversals. An international team of researchers (Austria, Switzerland, Finland, Australia, Germany) modeled the impacts of an extreme SPE under different geomagnetic field strengths, focusing on changes in atmospheric chemistry and surface radiation using the atmosphere–ocean–chemistry–climate model and the radiation transfer model LibRadtran. Under current geomagnetic conditions, an extreme SPE would increase NOx concentrations in the polar stratosphere and mesosphere, causing reductions in extratropical stratospheric ozone lasts for about […]