Forbush decrease

A Forbush event (also: Forbush effect) is an observed sudden drop in the high-energy cosmic rays by a solar eruption. This happens because the solar wind keeps this high-energy particles from the earth. The event can be easily detected by a particle detector.

Namesake for the term Forbush event was the geophysicist Scott E. Forbush, who dealt in the 1930s and 1940s with the study of cosmic rays and discovered this effect.