Sunday, May 6, 2018

Moderately Strong Geomagnetic Storm Strikes Earth


A G2-class (moderate) geomagnetic storm hit the Earth on Sunday, May 6, according to a warning issued by the National Oceanic and Atmospheric Administration (NOAA). This is due to the arrival of a gaseous material flowing from a wide hole in the Sun's atmosphere.

The storming started on Saturday, May 5, at a G1-class (minor) level and its strength increased one day later. Therefore, the storm is more powerful than NOAA predicted few days ago.

“G1 (minor) geomagnetic storm conditions were first observed at 05/1759 UTC and G2 (moderate) conditions were first observed at 06/0218 UTC. Storm conditions were in response to the influence of a negative polarity coronal hole/high speed solar wind stream. Minor geomagnetic storm conditions are expected to continue over 05-06 May,” NOAA informs on its website.

Geomagnetic storms can increase the density and distribution of density in the upper atmosphere, causing extra drag on satellites in low-earth orbit. The local heating also creates strong horizontal variations in the in the ionospheric density that can modify the path of radio signals and create errors in the positioning information provided by GPS. While the storms create beautiful aurora, they also can disrupt navigation systems such as the Global Navigation Satellite System (GNSS) and create harmful geomagnetic induced currents (GICs) in the power grid and pipelines.

G2-class storm can cause voltage alarms and transformer damage in high-latitude power systems. When it comes to possible impact on spacecraft operations, in result of such storm, corrective actions to orientation may be required by ground control. Moderately strong geomagnetic storm can also spark auroras and cause fading of HF radio propagation at higher latitudes.

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