Solar flares and coronal mass ejections.

Michael

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http://sdo.gsfc.nasa.gov/assets/img/latest/latest_1024_0304.mpg

Today's "dark filament" eruption in the northern hemisphere got me thinking more about solar flares and the different types of coronal mass ejections. There seem to be two prevalent ways for a CME to occur, from "circuit disruption" events in very "high energy" coronal loops, and "dark filament" eruptions that tend to produce very significant CME's if not particularly large spikes in the x-ray spectrum.

The first type of flare is what Alfven would have described as a "circuit disruption" type of flare that "pinches" the coronal loop plasma to the point of failure at some point along the loop. The resulting circuit disruption process releases the total circuit energy into the mass ejection process. These types of flares produce LARGE spikes in the x-ray spectrum, and tend to produce very high velocity particles that can reach earth in as little as 15-20 minutes. These types of flares can produce fairly significant sized mass ejections, but that isn't always the case.

[0908.0813] Generation of large scale electric fields in coronal flare circuits

The second type of solar flare is the type that can be seen today in the 304A wavelength. There are "dark filaments" in the solar atmosphere that can "erupt" outward. The darker materials can be seen against the lighter background in not only the 304A images, but also in many of the iron ion wavelengths, including 335A and 211A. These types of dark filament eruptions tend to produce very little in the way of x-ray output as the filament turns outward, but they do tend to produce fairly significant amounts of mass flows, or CME's. They tend to be the "most dangerous" type of solar flare IMO.

Unfortunately this type of flare/CME event is currently NOT being "predicted" by any statistical/scientific means that I am aware of at the moment, whereas the first type of flare is being 'predicted' by tracking sunspot patterns in the photosphere and grouping them into "categories".

Index of /ftpdir/forecasts/daypre
Flare Prediction System

Be forewarned that there is a timing problem, and therefore a data collection problem in the solarmonitor data as it relates to past predictions, but they accurately show the current NOAA predictions for the day.

I'm currently working on a similar "grouping" and categorization method for "dark filament" eruption events. There seems to be an association between the size of the dark filament and the likelihood of eruption. The more mass in the dark filament, the more likely it also will produce a "large" coronal mass ejection event. The proximity to "active regions" also seems to play a part in the "stability' factor of the dark filaments.

The two other factors in filament eruption processes seem to be related to the height of the filament in the atmosphere and the "speed" of the materials in the filament. There's a really good SDO closeup image of a "partial" dark filament eruption that I'll try to round up a bit later today and post to the thread. I will also try to round up some examples of the various 'categories' I'm using. I'd like to get some feedback to be sure my grouping methods seem logical and easily distinguished by someone other than myself. :)

It should take a few hours for the latest dark filament eruption CME to become observable in the LASCO C-2 and C-3 images, but I will post those images once the dark filament eruption that is observed in the 304A SDO images become visible in the LASCO images. I'll also post links to the STEREO images of the CME as well.
 

Michael

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http://www.spaceweather.com/swpod2010/18oct10/filamenteruption.mpg

FYI, this was a link to a "partial" dark filament eruption. This is a closeup SDO image in the 304A wavelength. As you can see the "darkness" of the filament is rather a "transitory" state. Sometimes a part of it 'heats up', particularly where part of the filament splits off.
 
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Michael

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SOHO has been one of the coolest missions ever.

I agree. It's also been one of the most amazingly reliable missions ever. I still watch the C-2 and C-3 images every day. :)

FYI, I'll try to layout the coding system that I've been using over the next few days and weeks, along with some SDO image examples of the variations in dark filaments by category. Some of the key stability and categorization issues relate to the proximity of the thread to active regions, the length of the filament, the density of the filament, it's location in the atmosphere (high or low), it's movement, it's speed, etc.
 
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Michael

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3-day GOES X-ray Flux Monitor

It looks like the sun released a fairly large (M class) flare in our general direction. From the STEREO images, it does look to have produced a fairly large CME. There could be some interesting aurora from that CME in a couple of days. :)
 
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Michael

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http://stereo-ssc.nascom.nasa.gov/browse/2011/09/06/behind_20110906_cor2_512.mpg
http://stereo-ssc.nascom.nasa.gov/browse/2011/09/06/ahead_20110906_cor2_512.mpg

From the looks of the CME, most of the mass seems to be pointed somewhat upwards, out of the planetary plane, but we could still get a glancing blow. FYI, this was the first type of flare, the circuit disruption type of flare. It typically produces large spikes in the x-ray spectrum and in this case the discharge can even been seen in 1600 and 1700A images as well. That was a pretty nice M class flare. ;)
 
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Michael

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Michael

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http://stereo-ssc.nascom.nasa.gov/browse/2011/09/07/ahead_20110907_cor2_512.mpg

Based on the early COR images, I'd say that while the bulk of the material in the CME was directed up and away from the planetary plane, some of the material was directed our way. We should see some effect in the ACE data over the next couple of days, probably on the 9th. We're already seeing an increase in high energy protons from that event.
 
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Michael

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For anyone following the progress of the CME, you might appreciate the following links:

NICT Real-Time Magnetosphere Simulation
Real-time Magnetosphere Simulation

The movies are also really fun. The solar wind has been surprisingly calm for the past few days although we did see a nice uptick in high energy protons after the M and X class flares from 11283. We should start seeing something from the last flare by the 9th. I'm not sure about the trajectory of the M class flare, but it seemed to be directed up and away from the planets, whereas the last flare seemed to be somewhat larger and less focused in a single direction. We probably will see some auroral activity from the X flare, and it should become visible in the ACE data in about 24-48 hours.
 
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Michael

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This is a computer simulation of what the Earth's magnetosphere looks like while experience a "gentle breeze" of the solar wind blowing past the Earth's magnetic field.

http://www2.nict.go.jp/y/y223/simulation/realtime/images/test_6.20110909114115.jpg

Here's what the same image looks like when it's being impacted by a CME event, in this case that first X class flare:

http://www2.nict.go.jp/y/y223/simulation/realtime/images/test_6.20110909121106.jpg

Notice all the white and red areas and how the amount of current flow through the magnetosphere "lights up" the magnetosphere. Notice too that the density of the solar wind has jumped from a few protons per CC/sec to over 30 protons per CC/sec.

The net effect of a CME is that a large density of protons and electrons stream into the Earth magnetosphere, lighting up the aurora along the way.
 
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