The heliosphere is permeated with energetic particles of different compositions, energy spectra and origins. Two major populations of these particles are galactic cosmic rays (GCRs), which originate from outside of the heliosphere and are constantly detected at Earth, and solar energetic particles (SEPs) which are accelerated at/near the Sun during solar flares or by shock fronts associated with the transit of coronal mass ejections. Enhancements in energetic particle fluxes at Earth pose a hazard to humans and technology in space and at high altitudes. Within the magnetosphere, energetic particles are present in the radiation belts, and particle precipitation is responsible for the aurora and for hazards to satellites. Energetic particles have also been shown to cause changes is the chemistry of the middle and upper atmosphere with potential influence on regional or even global climate, and, on a shorter time-scale, can influence the global electric circuit. Furthermore, such particles can produce cosmogenic radionuclides within the atmosphere, which become stored in natural terrestrial archives. The records of these trapped particles make a quantitative proxy for long-term solar variability. This meeting will aim to address the passage of energetic particles through the heliosphere, their detection at Earth and the effects they have on the terrestrial atmosphere when they arrive. This session will aim to address the passage of energetic particles through the heliosphere, their detection at Earth and the effects they have on the terrestrial atmosphere when they arrive. It will bring together scientists from several fields of research in what is now very much an interdisciplinary area.  The session will allow sharing of expertise amongst international researchers as well as showcase the recent advances being made in this field, which demonstrate the importance of the study of these energetic particle populations.