More stuff we need to know

At According to Hoyt Stephanie Osborne continues her attempt to educate us about Solar, Space, and Geomagnetic Weather, Part III.

the Earth’s magnetic field (aka magnetosphere aka geomagnetic field) is not nice and symmetric. This is because the solar wind is pushing on it. So the side toward the Sun has a “bow shock” and is compressed, and the side away from the Sun is stretched out into a tail. Like this:



The more charged particles hit our magnetosphere, the more get caught in the Van Allen Belts (VAB), and the more apt we are to have atmospheric effects. So an enhanced solar wind stream (EWS) from a coronal hole can generate some interesting phenomena.

But the granddaddy of those phenomena is caused by a coronal mass ejection hitting Earth. Because those suckers are (relatively) dense and VERY energized. And it might look something like this:



Worse…remember how flares are the detonations caused by “magnetic reattachment”? Well, if a CME is powerful enough, it can put so much stress on the magnetotail (that part stretched off to the right in these images) that it can snap off, and reattach closer to Earth! The energy feedback from THAT can get pretty powerful, too!

How energetic IS all this stuff?

Well, these events can actually raise the temperature of the outer layers of the Earth’s atmosphere (the thermosphere, aptly named) sufficient to cause it to expand. This affects us, because that increases drag on satellites and spacecraft, and can cause the orbits of satellites to decay and re-enter well before they were intended. This is really bad if it’s something important, like a weather satellite during hurricane season. After all, if the people of Galveston had had weather satellites in 1900, the city could have been evacuated well before it got hit, because they would have known it was coming for days. If we DON’T have weather satellites because we’ve lost ‘em to increased atmospheric drag, we might as well go back to those days, as far as weather prediction is concerned. Ditto communications satellites. Don’t even mention GPS.

...Disruption of the Earth’s magnetic field can be a problem. It can disrupt radio communication (including cell phones) rather severely. It can damage satellites that remain in orbit. It can generate “induced current” in any lengthy conductor.

...When these truly huge induced currents hit things like transformers and circuit breakers and power stations, they can quickly overload them. This, in turn, can (and has) cause(d) blackouts and brownouts, particularly in parts of the country/world where the power grid is not robust enough to handle significant surges. (Given that most large substation transformers are still hand-built, and have a lead time of months between determining need and installation, that could be a real problem.)

...Long pipelines, like the Alaskan Pipeline, can be affected as well. In fact corrosion is occurring at a higher rate than expected because its northerly location exposes it to such induced currents all the time (remember that the ends of a bar magnet’s field are open). And there are plenty of those.

Read more here.