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Posts tagged with "polar cap absorption"

On 23 January 2012, a magnitude M8.7 (M9-class) X-ray flare erupted in NOAA Active Sunspot Region (AR) 1402. The long-duration flare peaked at 0359 UTC. This flare triggered a proton event, resulting in an S3 (Strong) Radiation (Proton) Storm and a Polar Cap Absorption (PCA) event over the polar regions.

This PCA event caused a complete radio blackout over high-latitude and polar regions. This results in any trans-polar radio paths to become as dead as a rock.

This solar proton radiation storm is the strongest since September, 2005, which was during the last solar sunspot cycle, Solar Cycle 23.  An S3-level radiation storm causes airlines to divert air traffic away from the polar regions.  This level of a storm could also cause satellite issues, with GPS and communications being affected.  Additionally, those living and working in polar regions must take precautions not to be exposed to this radiation.

At the end of the video, you will see the Coronal Mass Ejection that was released by this flare. This is a fast-moving CME and it is expected to arrive at Earth on January 24, 2012, triggering a G1 to G3 level geomagnetic storm.

X-ray flares are huge explosive releases of energy, including X-ray and light energy. This light and X-ray energy reaches Earth at the speed of light—eight minutes later. When it reaches Earth, it causes the ionosphere to become highly energized, so much so that the D-region (the lowest region) absorbs shortwave, and medium wave, frequencies, blocking them from going any further (and being refracted or propagated long distances around the world).

Credit: NASA SDO / AIA / LASCO / STEREO

(Source: youtube.com)