Saturday, December 29, 2018

Minor Geomagnetic Storm Hits Earth


A G1-class (minor) geomagnetic storm hit the Earth on Friday, December 28, according to National Oceanic and Atmospheric Administration (NOAA). Our planet entered a stream of fast-moving solar wind, which triggered the storming.

The gaseous material that caused the minor storm is flowing from a canyon-like hole in the sun's atmosphere. In result of the storm, visible auroras are concentrated around Earth's poles and weak power grid fluctuations could occur. The current G1-level storming could also have minor impact on satellite operations. 

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 in the power grid and pipelines. 

NOAA informs that solar activity is expected to be very low during the next three weeks. However, geomagnetic field activity is expected to reach active levels on December 29, January 4 and 16 due to recurrent, coronal hole high-speed stream (CH HSS) influence. 

Fast CH HSSs can impact Earth’s magnetosphere enough to cause periods of geomagnetic storming to the G1-G2 (moderate) 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.

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