Sunday, October 14, 2018

Minor Geomagnetic Storm May Hit Earth on Sunday

A G1-class (minor) geomagnetic storm may hit the Earth at late hours of Sunday, October 14, according to National Oceanic and Atmospheric Administration (NOAA). The storming is due to a stream of high speed solar wind flowing from a ragged hole in the sun's atmosphere, which is expected to reach the magnetic field of our planet.

Minor geomagnetic storm can trigger auroras visible around Earth's poles and weak power grid fluctuations. Such storm could also have minor impact on satellite operations.

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. 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 although solar activity is expected to be very low until at least November 3, next minor geomagnetic storm may occur on October 19. This storm could be triggered by multiple, recurrent coronal hole high speed streams (CH HSSs) that could become geoeffective.

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.