Today I learned about the solar phenomenon known as #ParkerSpiral -- which means that even a #CME that isn't Earth-facing could still affect Earth! I did not know about that!

"July of 2012 witnessed the eruption of a very large and fast solar coronal mass ejection (CME) (see NASA STEREO Observes One of the Fastest CMEs On Record and #Carrington-class CME Narrowly Misses Earth ). While not directed at Earth, it was sufficiently large that it could have seriously disrupted the global electrical #infrastructure. The event did impact STEREO-A of NASA's heliophysics fleet which provided a host of measurements (see Sentinels of the Heliosphere).

"One of the conditions which contributed to the high speed of this event is that two smaller CMEs were launched a little earlier, and these events cleared out much of the solar wind material, leaving little to slow the outflow of the July 23 event (UTC).

"In the visualizations below, generated from the Enlil space weather model, green represents particle density, usually protons and other ions. In green, we see the Parker Spiral moving out from the sun generated by the sun's current sheet (Wikipedia). Red represents particles at high temperatures and shows the CME is hotter than the usual solar wind flow. Large changes in density are represented in blue. These three colors sometimes combine to tell us more about the characteristics of the event (noted in the 3-color Venn diagram below).

"However, if this CME had struck Earth's magnetosphere, which has a much stronger magnetic field, the changing magnetic field would induce much larger voltages in systems with long electrical conductors, such as power lines that run over long distances. These significantly higher voltages can damage power transformers."

https://svs.gsfc.nasa.gov/4167

via Spaceweather.com

Sunday, July 30, 2023

"GEOMAGNETIC STORM WATCH (G2): Geomagnetic storms are possible on Aug. 1st when a #CME is expected to hit Earth's magnetic field. Minor G1-class storms are likely with a chance of escalating to category G2. The CME was hurled almost directly toward Earth by the eruption of a magnetic filament in the sun's northern hemisphere on July 28th. Aurora alerts: SMS Text

"#PROTONS ARE *STILL* HITTING EARTH'S ATMOSPHERE: For the second day in a row, energetic protons from the sun are raining down on Earth's atmosphere. This is called a "radiation storm" (S1-class), and it was caused by a magnificent eruption on July 28th.

"The blast site was hidden from view just behind the sun's northwestern limb. Earth-orbiting satellites registered an M4-class solar flare, but the underlying explosion was stronger. It was probably an X-flare partially eclipsed by the edge of the sun.

"How can a sunspot not facing Earth send so many protons in our direction? The answer is 'the #ParkerSpiral.' Take a look. As the sun spins, its magnetic field spirals like water flowing from a twirling lawn sprinkler. Lines of magnetic force emerging from behind the sun's northwestern limb (where the explosion happened) spiral back and make a direct connection to Earth. It's a superhighway for energetic protons.

"This #RadiationStorm looks like it will continue at S1 levels for at least one more day. Its main effect is a polar cap absorption event (PCA) inside the Arctic Circle. Right now, #shortwave radios around the north pole aren't working very well."

https://spaceweather.com/repeat_images/parkerspiral2.png

#Spaceweather #SolarFlares #solarcycle25