sub·​storm | \ ˈsəb-ˌstȯrm How to pronounce substorm (audio) \

Definition of substorm

: 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

Examples 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, "Scientists Discover What Makes Northern Lights Dance," 24 July 2008

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'substorm.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of substorm

1961, in the meaning defined above

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The first known use of substorm was in 1961

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Cite this Entry

“Substorm.” Dictionary, Merriam-Webster, Accessed 12 Aug. 2020.

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