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
Tim BeardsleyExamples of substorm in a Sentence
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
Examples are automatically compiled from online sources to
show current usage.
Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
Brandon Keim, WIRED, 24 July 2008
Cite this Entry
“Substorm.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/substorm. Accessed 4 Jul. 2025.
Copy CitationLove words? Need even more definitions?
Merriam-Webster unabridged
Share