February 16th, 2015 : The “Coronal Hole” Red Aurora

Traditionally I think of the aurora being generated from a sun event. Often C-class flares, M-class flares, and X-class flares (the largest) hurtle plasma towards at the earth resulting in brilliant auroras. I have dug into the science of auroras during previous posts, and wrote about some of the science of the auroral colors and why the aurora can go from a nice show to a great show.  However, last nights aurora event was generated by a “Coronal Hole” in the sun. That term was new to me, and although it sounds like a headline from an end of days article, it’s really not that bad!

Coronal holes are a simple concept. The sun normally has a stable magnetic field that controls solar winds and energy from the sun. During a coronal hole event, magnetic field lines extend far away from the sun and allow high speed solar winds to escape. Solar wind speeds may exceed 10,000,000 km/hr! Translating that to terms I understand more, solar winds can travel at 500 miles/second. That’s a quick commute to work, or in this case the earth!  If the coronal hole is ‘geo-effective’ it means that those solar winds are headed towards our planet. These events can lead to a lot of high energy resulting in red and multicolored auroras even during times of low solar activity. (http://www.spaceweatherlive.com/en/help/what-is-a-coronal-hole, http://www.exploratorium.edu/spaceweather/holes.html)

Last night’s show was stopped at 10:30 due to clouds over Fairbanks. From 8:30 – 10:30 it remained subtle, but beautiful. The high energy from the coronal hole produced a quickly changing, but not well defined red aurora. I hope you enjoy!

7 thoughts on “February 16th, 2015 : The “Coronal Hole” Red Aurora”

  1. The colors may not be as “brillliant” but there is certainly something very special about the muted melding of reds, purples, yellows and greens. The crooked spruce trees give the images even more flow and movement while the uprights give the eye a place to rest and focus. Well done!

  2. The Space Weather Live image reminds me being really close and looking into an eye. Your explanations are so helpful; otherwise, I might not understand nearly as much of this. I find this so interesting partly because a portion of my now three-year-old dog’s registered AKC name is “Aurora Isbre” from the Latin for “sunrise” and Norwegian for “ice.” I thought it a fitting name for a puppy born in January and going home to live in Minnesota. (I am typing this on a mighty cold night.)

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