Sunspot

A sunspot is a comparatively dark, magnetically concentrated region on the Sun’s photosphere. Its lower temperature makes it appear darker than the surrounding surface.

Solar magnetic field: The magnetic field generated by the Sun’s electrically conducting plasma and shaped by its rotation and internal flows. Concentrated magnetic fields in sunspots hinder the upward flow of hot plasma.
Solar dynamo: The process by which motion in the Sun’s electrically conducting interior generates and sustains its magnetic field. It supplies the magnetic field whose emergence produces sunspots.
Carrington event: The exceptionally intense geomagnetic storm of 1859, associated with a major solar eruption. A large sunspot group preceded the eruption that drove this famous space-weather event.
Space weather: Conditions in space influenced by solar activity, including energetic particles, radiation, and changing magnetic fields. Active sunspot regions can produce flares and eruptions that disturb near-Earth space.
Facula: A bright magnetic feature in the solar photosphere, especially conspicuous near the solar limb. Faculae are magnetically active like sunspots but appear brighter than the surrounding photosphere.
Solar convection: The transport of energy by rising hot plasma and sinking cooler plasma in the Sun’s outer interior. Sunspot fields inhibit this heat-carrying motion, leaving the spot cooler than nearby photosphere.
Solar cycle: The roughly 11-year variation in solar activity, including changes in sunspot number and magnetic polarity. Sunspot abundance rises and falls as part of this recurring activity cycle.
Maunder Minimum: A period from about 1645 to 1715 when few sunspots were recorded and solar activity was unusually low. Its sparse sunspot record illustrates long-term departures from the usual solar cycle.
Solar flare: A sudden release of magnetic energy in the solar atmosphere, producing radiation across the electromagnetic spectrum. Flares often erupt above magnetically complex sunspot regions.
Plage: A bright region in the solar chromosphere associated with concentrated magnetic fields. Plage often surrounds sunspot groups but is observed as a bright chromospheric feature.

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