The Atmosphere and Radiation: Screening or Generating?

It is widely understood that the atmosphere shields Earth from harmful radiation. However, it not only absorbs the energy of galactic and solar cosmic rays but also acts as a particle source, producing large fluxes of electrons, gamma rays, and neutrons. These particles are created through various mechanisms, including relativistic runaway electron avalanches (RREAs), which appear as thunderstorm ground enhancements (TGEs) when detected at Earth’s surface, and gamma glows above violent tropical thunderstorms. The Global Electric Circuit (GEC) controls the increased fluxes of particles originating from the atmosphere. Thunderstorms generate strong electric fields that stretch across large areas within and around storm systems. Charge separation in thunderclouds, driven by updrafts of warm air and interactions among hydrometeors, creates opposite dipoles within the cloud. The atmospheric electric field contains upper and lower dipoles, which accelerate free electrons toward both open space and the Earth’s surface. Many free electrons are present in the troposphere from extensive air showers (EASs). Electric fields produced by strong thunderstorms transfer energy to these electrons, accelerating them and, under certain conditions, causing electron-photon avalanches. These avalanches travel through large parts of the atmosphere and cover wide areas once they reach the Earth’s surface, greatly boosting the level of natural gamma radiation (NGR) and creating gamma glows over vast areas above tropical thunderstorms.