substorm

noun

sub·​storm ˈsəb-ˌstȯrm 

: a disturbance in the magnetosphere that manifests as increased activity in the aurora (see aurora sense 3) and that is caused by an influx of high-energy particles from the sun (as from a solar flare)

Even when the sun is being well behaved, parcels of plasma shoot sporadically toward Earth's dark side, prompting a bright aurora and intensifying radiation belts. These events, called substorms, last only a few hours, but they occur several hundred times a year and are quite capable of disrupting satellites …

Tim Beardsley

Example Sentences

Recent Examples on the Web

Ninety seconds after the satellites sensed the substorm starting, ground observatories witnessed a Northern Lights display suddenly brighten and dance. Brandon Keim, WIRED, 24 July 2008

Word History

First Known Use

1961, in the meaning defined above