A G2 Class geomagnetic storm is expected to occur on Earth this Thursday, April 14, thanks to a "dead" sunspot flinging out a coronal mass ejection (CME) of plasma and solar material towards Earth on April 11. Good news for aurora hunters as the Northern Lights could be seen as far south as New York.
The geomagnetic storm is due to an increase in the plasma that the Earth receives from the Sun. The CME was generated by a sigmoid structure, an S-shaped magnetic filament found in the Sun's corona that produces a "flare" eruption, from a region that until recently sported a sunspot. Due to convection in the Sun's surface, the "corpse" of spot AR2987 was broken apart yesterday, leaving behind a seemingly quiet solar surface.
But magnetic trouble rumbled underneath that unblemished surface, generating an eruption that hurled the debris toward Earth, as reported by SpaceWeather.com.
The CME on April 11, 2022. credit: NASA/SDOAIA
Sunspots are cooler areas of the Sun caused by magnetic fields that weaken the processes by which heat rises to the Sun's surface. Although the spots themselves are emitting less energy than surrounding areas, they are associated with flares and CMEs where plasma bursts into space. When these occur charged particles stream off the Sun. Those that head in our direction can be funneled by Earth's magnetic field towards the geomagnetic poles. When they strike the upper atmosphere they can produce auroras that range from tantalizing to breathtaking.
The associated auroras for this geomagnetic strom have an expected KP of six – on a scale that goes from zero to nine and averages a two or a three on a regular night – so should put on a good show. They are expected to be visible in mid-to-high latitudes, as south as Scotland in Europe and Illinois in North America.