Sunday, August 26, 2018

Strong Geomagnetic Storm Hits the Earth


A G3-class (strong) geomagnetic storm hit the Earth this weekend when a high-speed stream of solar wind arrived at our planet. The gaseous material was ejected from the sun during a coronal mass ejection (CME) that occurred few days earlier.

In general, geomagnetic storms can increase the density and distribution of density in the upper atmosphere, causing extra drag on satellites in low-earth orbit (LEO). 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 in the power grid and pipelines.

Fast coronal hole high speed streams can impact Earth’s magnetosphere enough to cause periods of geomagnetic storming to the G1-G2 levels; although rarer cases of stronger storming may also occur. The larger and more expansive coronal holes can often be a source for high solar wind speeds that buffet Earth for many days.

G3-class storms have the power to affect power systems causing false alarms triggered on some protection devices, therefore, voltage corrections may be required. In result of such storming, surface charging may occur on satellite components, drag may increase on LEO satellites, and corrections may be needed for orientation problems. Furthermore, strong storms cause radio navigation problems and trigger auroras seen as low as Illinois and Oregon.

National Oceanic and Atmospheric Administration (NOAA) reveals that besides the current G3-class storming, which is currently fading to a G2-class (moderately strong), solar activity is expected to stay generally at very low levels at least until September 15. However, active levels may occur on September 3-4, September 7 as well as September 11-15, causing more geomagnetic storms.

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