We've talked about cannibal CMEs here on the blog a few times, a term for when
a faster moving coronal mass ejection overtakes a slower CME that started
before the faster one. The resultant isn't just more material, the overtaking
one compresses the original into a denser one capable of more impact on the
Earth or wherever it hits. There's an even bigger than typical Cannibal CME
coming in
according to SpaceWeather.com.
CANNIBAL CME ALERT: A series of M-class flares over the weekend hurled multiple CMEs toward Earth, as many as four or five. According to a NOAA model, the first two CMEs are merging to form a single Cannibal CME. Strong G3-class geomagnetic storms are possible when it reaches Earth on July 30th. Subscribers to our Space Weather Alert Service will receive an instant text message when the CME arrives.
Bonus: Watch NOAA's animated forecast model of the first two CMEs merging to form a Cannibal.
The Cannibal CME is clearing the way for perhaps 2 to 3 more CMEs following behind it. SOHO coronagraphs show a wagon-train of clouds leaving the sun on July 28th:
The first and most potent of these CMEs was launched by an M9.9-class solar flare from sunspot complex AR3765-67 on July 28th (0157 UT): movie. The CME will fly into a void created by the earlier Cannibal CME. With little interplanetary material to slow it down, the storm cloud should reach Earth no later than July 31st. A preliminary NASA model supports this forecast.
Even if the Cannibal CME fails to spark a strong geomagnetic storm on July 30th, the arrival of more CMEs on July 31st could push storm levels to category G3 (Strong) or beyond. This would set the stage for mid-latitude auroras visible from Europe and the USA.
You may have heard that on Tuesday, July 23, the sun launched the biggest solar flare of this cycle and going back to the early '00s (cycle 23) at X14. That flare isn't part of this coming potential storm because of the tremendous good luck we had in where the flare erupted from. It erupted from the far side of the sun and was pointed completely away from Earth. For comparison, the X-class flare that started the massive, historic G5 geomagnetic storm of early May wasn't as strong as the X14 from the far side; the flare on May 10 was X5.8. There were a few Earth-directed flares in those few days in May, but the strongest flare in early May was X8.8 and that was the strongest of Cycle 25 - until last Tuesday's X14.
Plot of the solar flares around July 23rd's X14 flare. Solar Orbiter was over the farside of the sun when the explosion occurred on July 23rd, in perfect position to observe a flare otherwise invisible from Earth.
Geomagnetic storms like those being expected from the incoming CMEs are
usually most evident in shutting down high frequency (shortwave) radio
propagation. They can introduce paradoxical improvements in HF and VHF
propagation, especially during periods when the geomagnetic K-index is
dropping. We tend to look at the numbers posted of the planetary K-index (here, for example) and think of them as static or very slow moving,
but much like wind gusts during any sort of storm, the K-index can go up and
down on shorter time intervals than the three hour averages plotted there.
I'll have to cruise around the bands and see how they sound "up here".
ReplyDeleteThe last few times I've seen predictions of a geomagnetic storm from SpaceWeather they never materialized. Probably a good thing, and I went with this one mainly because it just seemed more possible with it being several flares/CMEs instead of just one. OTOH, they were pretty much all M-class flares and I firmly believe most of us can fart more damaging problems than that. I know I can.
DeleteHold on to your socks, everybody...
ReplyDeleteINCOMING!!
We'll see how it shakes out, SiG.
What level CME created the Carrington Effect?
ReplyDeleteOr what level CME is expected to cause notable power outages, maybe fires?
Thanks
The Carrington Event was a once in recorded history thing, although there's some evidence that something similar may have happened once or twice since year zero (AD). Since there were no measuring instruments like we use today available in 1859 when it happened, it's hard to extrapolate numbers onto it.
DeleteBack in November of 2003, toward the end of cycle 23, there was a super flare that was genuinely scary and the kind of flare to worry about. The biggest flare seen since the satellite age started, it was classed as X28 in retrospect - because it saturated the X-ray detectors on the satellites and they couldn't measure it properly. Why didn't it harm us? Because it was on the limb of the sun and the CME went 90 degrees to our direction. That's another important variable that makes a big difference and just resists putting numbers on. The combination of how big the CME is and exactly where it points is what matters. A smaller CME pointed directly at us can do more than a big one pointed away from us.
I've seen it argued that the big solar storm of the past May 10 might have been the same size as (or close to the size of) the Carrington event. In a way that's very good, because the grid was basically fine, with no widespread damage. (I'm not aware of any damage to the power grid). Maybe we could dial back the angst and worry about every little solar burp.
There have been tests of cars with controlled EMPs that can put out a big enough pulse to cause them to stall. Turning them on again was all it took. What are you going to do if your engine turns off? I bet you'll turn the ignition switch as a reflex.
As for how big a flare to cause power outages, I don't have numbers to compare to. There has been one CME in history that damaged parts of the grid (it shut down power in Quebec) and that was in the last peak of the 1990s (1996?).
Just another thing we a humans have not control over at all. The only thing we can do on earth is to try and prepare for them when they hit us. I keep waiting for one that stops all the cars in the world from moving. Then things will get real interesting on this earth. I wonder if that would stop some of the wars going on around this earth? It sure would cut down on electrical usage, maybe ever lower the electric bill for the year.
ReplyDeleteHeltau
I think it's dead certain there's no such thing as a CME that could "stop all the cars in the world." If nothing else, they seem to have to be on the sun-facing side of the planet when the mass ejection gets here. The tests I've seen documented created a Nuclear EMP-type of pulse. Cars would shut down but restart when the driver turned the ignition switch. Universal software fix: turn it off and on again.
DeleteI think the only thing certain is it would be better to be driving an old, conventional ignition car than the more electronic versions, or an EV.
You're referring to the 2004 EMP testing? I've read the report and found it interesting that they borrowed vehicles from other agencies and were required to return them in "Good running order" per document.
DeleteThat said I understand they slowly dialed up the emp pulse until malfunctions occurred then stopped due to "return in good running order" requirements. No test to destruction. Only one pickup truck had to be towed to a repair shop in the exercise.
That said MY Concern is the Battery Management System in lithium battery packs. You know the ones that they show "interesting" burning problems now and then. Like the Telsa Truck recently.
If that fails during a CME-EMP style event what excitement that will be in your garage.
Or as they are getting popular in Solar installs a Telsa Power Wall in your home or business. Exciting as in Fire Department just lets it burn out.
Delete"You're referring to the 2004 EMP testing?"
DeleteIt's "long ago and far away" and I don't really remember. Since it was in some stuff I was doing at work in the 2010 time frame, it probably was those experiments. I recall watching videos of the tests, but that's about all. The important point is that while they have some similarities, an EMP isn't a CME. Don't conflate the two. Important details, like rise time of the energy, and the Fourier transform of the energy pulse from the time to frequency domain are very different. My apologies for going down that road.
Even more confusing is that no two CMEs are necessarily the same. The expected geomagnetic storm never appeared. The first impact of the expected CMEs was at 0030 UTC (last night, east coast time). The most it made was a minor, G1 storm for a couple of hours, 2 to 5AM EDT. They're still saying more appears to be coming later today.
A fun thought experiment is what would have to happen for a CME which stopped all the cars.
ReplyDeleteGiven the CME has to be facing earth. To stop all the cars, the duration of the CME would be, at minimum, one full earth rotation.
As the sun also 'rotates' with respect to earth, how much of the sun's surface would the CME cover for that duration?
Further, the CME would be a value sufficient to stop all the cars and that value would maintain for that entire duration
The sun's rotation is around 28 Earth days, so a spot on the sun would move 10 to maybe 13 degrees (the sun isn't solid so it's not like every latitude rotates at the same rate).
DeleteThat said, that's not how CMEs work. The CME is thrown out from the sun and how long it lasts at Earth depends on how long the ejection lasts, front to back, when it gets here. They're not continuous streams out of the sun, they're explosions - short duration in time. Interaction between the particles and our magnetic field plays a big role.
I love it when you talk like that.
DeleteYes, the variables. It's why I kept my previous so general. Rotation in quote marks to show that sun's movement is unlike that of a solid. With respect to that 'rotation' I meant only that part pointing at earth.
All to say that a CME would be long in duration (relative to previous CMEs), always pointing towards earth, as well as being at continuous value (class) for that duration.
For the purpose of my thought experiment, it matters not if such CME is a pulse or stream. The effects would need be continuous.