Sunday, June 14, 2015

Minor Geomagnetic Storm Hits Earth

The indicated region of the Sun was the source of June 9 CME that triggered geomagnetic storm on June 14. Credit: NASA/SDO

G1 (Minor) geomagnetic storm conditions were observed between 9:00-12:00 UTC (5:00-8:00 a.m. EDT) on June 14, due to the influence of the Sun's coronal hole high speed stream. G1 levels persisted until around 14:00 UTC (10:00 a.m. EDT) today when geomagnetic field conditions are expected to weaken to below NOAA (National Oceanic and Atmospheric Administration) scale thresholds. A geomagnetic storm is a major disturbance of Earth's magnetosphere that occurs when there is a very efficient exchange of energy from the solar wind into the space environment surrounding Earth. These storms result from variations in the solar wind that produces major changes in the currents, plasmas, and fields in Earth’s magnetosphere.

Today's geomagnetic storm is connected with the arrival of a coronal mass ejection (CME) that left the Sun on June 9. CMEs are huge explosions of magnetic field and plasma from the Sun's corona. The ejections typically take several days to arrive at Earth, but have been observed, for some of the most intense storms, to arrive in as short as 18 hours.

Minor radio blackouts were also observed over the past 24 hours. The largest was at 00:59 UTC, on June 14 (9:59 p.m. EST, June 13).

Solar activity is expected to be low with a chance for M-class flares on days one and two (June 14-15) and expected to be low with a slight chance for an M-class flare on day three (Jun 16).

During storms, the currents in the ionosphere, as well as the energetic particles that precipitate into the ionosphere add energy in the form of heat that 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 and create harmful geomagnetic induced currents in the power grid and pipelines.

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