Wednesday's solar storm and the aurora -- a question

[profdant139]

I just read online that there was a very big solar flare on Saturday and that satellite operators are worried about damage on Wednesday, April 2. But yet the aurora forecasts are fairly quiet for the next few days. I think I'm missing something about the relationship between solar storms and the aurora.

I suppose it's possible that the folks in charge of preparing the aurora forecast website haven't yet updated their information and that Wednesday is going to be spectacular. Not sure if this is going to hit before dawn on Wednesday or on Wednesday evening or what.

Does anybody have better information about what's happening? And can someone straighten me out on the interaction between flares and the aurora? Thanks in advance!

[Orion]

I think it worthwhile to point out that although this upcoming event will not produce any devastating effects on the Earth, I believe that a future event could. In 1859, the Earth was hit by a very large CME now referred to as the 'Carrington Event'. This is part of what Wiki has to say about it.
On September 1–2, 1859, the largest recorded geomagnetic storm occurred. Aurorae were seen around the world, those in the northern hemisphere even as far south as the Caribbean; those over the Rocky Mountains were so bright that their glow awoke gold miners, who began preparing breakfast because they thought it was morning.[2] People who happened to be awake in the northeastern US could read a newspaper by the aurora's light.[4] The aurora was visible as far from the poles as Cuba and Hawaii.[5]

Telegraph systems all over Europe and North America failed, in some cases giving telegraph operators electric shocks.[6] Telegraph pylons threw sparks.[7] Some telegraph systems continued to send and receive messages despite having been disconnected from their power supplies.[8]

This was in 1859, can you imagine what would happen if this happened now? It has been predicted that MILLIONS of transformers would blow all over the Earth. Communications would be down, it would take years to recover, if we could.
You could say that these events only happen every thousand years or so, but unfortunately, they happen all the time. Luckily though, they normally miss the Earth, it depends where the flare is on the Sun when it occurs. New research has revealed that in 2012, there was a massive CME from the Sun. This hit squarely the Earth's orbit where the Earth had been just a week ago! A week sounds like a lot, but draw a 1/4" circle at the centre of a piece of paper, The Sun, draw a much bigger circle around the Sun, the Earth's orbit. Now divide up this circle into 52 equal segments, each representing how far the Earth orbits in a week. Draw a tiny dot at one of the points, this is where the Earth was on that day in 2012. Now draw a flame coming from the Sun hitting the next point on the circle. That's how close it was.
This is probably the biggest natural disaster that the Earth could face, other than an asteroid strike, which is much rarer.

[profdant139]

Thanks to both of you for those explanations!

[GordonThree]

In other words, the FLARE emits electromagnetic radiation, that arrives at the speed of light (8 minutes). Flares themselves (x-rays, uv, microwave) don't usually cause aurora unless they are extremely powerful. They can blind satellites temporarily.

Coronal mass ejection (CME) - actual pieces of the sun, billions of tons of super heated hydrogen and helium are ejected by the flare and travel at close to the speed of light, but take a few days to get here from the Sun. This mass carries a lot more energy, and when it impacts our atmosphere, this is when we the Aurora. This mass is also what can damage satellites... it slows them down by increasing drag, heats them up (drag again) and delivers an electric charge to the hull which can short out sensors / antennas, etc.

For a really good show, and risk of satellite damage, the CME and our magnetosphere (the magnetic shield of the planet) have to have an attractive polarization, and a certain geometry. For example, when you try to force two magnets together, North to North they push away, but if you flip one magnet over so it is North to South, then they attract... same thing happens on a huge scale in the atmosphere. When the polarization lines up, the magnetosphere actually sucks the CME into our atmosphere, rather than deflecting it away.

Once the CME gets sucked in, the energy from that hot hydrogen and helium dumps into our ionosphere (where the ozone protects us). All that energy makes the oxygen and nitrogen glow as it absorbs and dissipates the excess energy. Billions and billions of watts of electrical energy are generated by a strong storm, and that energy can sometimes play havoc with power grids and radio operations on the ground.

[Orion]

This is what Spaceweather.com said about the event.

IMPULSIVE SOLAR FLARE SCRAMBLES RADIO SIGNALS: On Saturday, March 29th, the magnetic canopy of sunspot AR2017 erupted, producing a brief but intense X1-class solar flare. A flash of extreme UV radiation sent waves of ionization rippling through Earth's upper atmosphere and disturbed the normal propagation of terrestrial radio transmissions. Radio engineer Stan Nelson of Roswell, NM, was monitoring WWV at 20 MHz when the signal wobbled then disappeared entirely for several minutes:

CHANCE OF STORMS: The first of three or more CMEs en route to Earth are expected to arrive late in the day on April 1st. None of the incoming clouds is squarely Earth-directed. The series of glanciing blows, however, will rattle Earth's magnetic field and possibly spark auroras. NOAA forecasters estimate a 60% chance of polar geomagnetic storms on April 2nd.. Aurora alerts: text, voice

The first paragraph covers the actual flare itself which was a powerful 'X Flare'. The effect of this was immediate, or 8 minutes later, with some short wave radio signals being affected.

Presumably this flare and others at around the same time, ejected 'CMEs', Coronal Mass Ejections, or massive clumps of Solar material which, when making contact with the Earth's magnetic field, will form the Northern Lights. From what I can see, they are not expecting a massive display, but I was wrong once before, I think!