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Coronal Mass Ejection Research Project


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I am back to update where I am with my research of Coronal Mass Ejections. 

To start out, I need to go back to the very beginning. Being interested in Earth's severe weather, the Coronal Mass Ejection of June 22nd, 2015 gave a new interest in space weather and CMEs. I was looking up the parameters and tried to learn all of the basics, the solar wind, IMF, K and Kp indices, etc. There was a lack of severe weather at the time and it wasn't too long before the time of Hurricane Patricia that I began my research. I started out with Coronal Holes, but eventually I thought I might as well try to see if I can find a way to predict the time of CME arrivals. My goal for predicting a CME's arrival time was by using one satellite's Coronagraph imagery and the time of launch.

Using SOHO's LASCO C3 imagery, SDO's AIA 131 imagery and ACE and Wind solar wind data to try and find some sort of pattern. I made run after run after run of trial and error using different calculations and points in time from the imagery. I did eventually find a pattern and the image below is the final graph where I have points on paper. This begins a chain reaction to several new discoveries.


Here are the steps used per CME to put a point on the graph. 
1. Get the difference of the CME launch time to arrival time in hours. The launch time that I use is when the CME reaches 2.5Rsun from the surface of the Sun.
2. In the C3 imagery, get the point in time of when the CME first reaches the edge of the FOV and a second point in time when the opposite side of the imagery reaches the edge of the FOV. The difference between these two times in hours is the X-Axis in the graph above.
3. From step 2 get the time between the two imagery points and get the difference from the launch time. Divide the travel time from step 1 by this step's number and this is the Y-Axis on the graph.

Briefly moving forward to mid 2018 I was able to discover the exact base formula for what is seen in the image above. The formula is y=cos(pi*x)-(x/sqrt(pi/2)) and with adjustments made for the C3 image Field of View and L1 position it results to the graph below. I will say there was a huge amount of luck because a minimal amount of changes had to be made to the formula for SOHO's FOV and L1 position, compared to changes that would need to be made for the STEREO satellites.


So now we have a problem. There are multiple lines and I am now stuck because I was expecting one line. I was even marking out or skipping data points in the first graph thinking I made a mistake somewhere. It can't be due to changes of the distance from the Sun, or the pattern wouldn't exist. The Coronagraph FOV is near constant, so that is ruled out. Randomly shaped CMEs are also ruled out because again, the pattern wouldn't exist. This is where I step away from the project for a while until the CME of September 10th, 2017.

Sunspot region 2673 came and went and I am now back to my research project with a sort of cleared mind. The September 10th CME is what brought a major breakthrough. In SOHO's C3 imagery and STEREO A's C2 imagery you can see a bulge ahead of a larger trailing shock. I look around at other CMEs and I now know why there are multiple lines on the graph. A CME can have two faces, a leading and secondary shock. To say if the secondary shock was right behind the leading shock, given the distance from the sun to the secondary shock multiplied by sqrt(pi/2) gives the position of the leading shock. The 2D illusions are gone and now have the leading structure of CMEs. The lines on the graphs have a new name, Multipliers. The Multiplier is only determined by the Coronagraph imagery and not the overall CME. A very, very preliminary image from this time of the research is below to sort of show the shape.


Now looking back at both graphs at the top of the post, the first doesn't show all of the lines. It wasn't until I ran calculations on STEREO A's July 23rd, 2012 CME to find the lowest Multiplier. The old Multiplier 0, or M0, then became M2. At this current time I only know of 2 other M0 CME Coronagraph views from SOHO and STEREO B.

Like how the graph is created, the same process can be done to see what we are looking at through Coronagraph imagery by using the Multipliers. Each Multiplier's type of Coronagraph view and impacts are below.
M0 - These are still partially a mystery to me. What I currently know is that they are narrower CMEs and are closer they appear with a leading shock impact. 
M1 - These have a leading shock impact and are similar to M0 CMEs, but have a buckled outer shock as the secondary shock with a leading shock impact. 
M2 - A leading shock impact where the two view points are the leading shock. 
M3 - A leading shock impact where the two view points are a leading and secondary shock. 
M4 - A leading shock impact where the two view points are the secondary shock. 
M5 - A secondary shock impact where the two view points are a leading and secondary shock. 
M6 - A secondary shock impact where the two view points are the secondary shock.

I wanted to keep going and my next goal has changed to figure out the CME structure. I know how important it will be. Going into this I know of sqrt(pi/2) and I know where the leading and secondary shocks are. Knowing those things I did what I know best, messing around with the numbers until I found a pattern. Eventually run after run after run I was able to find the CME structure while comparing imagery and solar wind data. The result shows CMEs have 3 layers, a central core, a middle layer, and an outer layer. A direct impact through the central core will result in hitting 5 internal shocks. Going further, there is a half shock between each layer. The image below shows almost every type of impact possible and is to scale, but does not account for the correct curve.


A question would be how does the structure hold together? My guess is has something to do with the magnetic structure of CME's, but at this point it's something I can't answer. Another question would be how do the different shapes come together? My current answer would be that it is determined by the size of the central core and how explosive the CME is. If there is too much push the middle and outer layers will begin to buckle, but the chances are there are a few other factors as well. As for the internal shocks, I call them shocks for a reason. It varies, but CMEs can be shock driven at any shock. It can be almost similar to the arrival of the CME. As far as I currently know, CMEs can be shock driven all the way back to the last internal shock at minimum. 

As this is most likely new, I gave simple names to the constants and this is basically what I have used on a calculator. This is how the position of how each shock can be calculated.

A = sqrt(pi/2)       - This is used for the position of a shock
B = Second Root of A - This is used for the position of a half shock. Going past beyond the second root is uncertain and will require more research to be able to see if things become more detailed.

Examples of how I will refer to this is that the leading and secondary face of a CME is A0. The duration of the far shock is A0-A2. An impact through the edge of the central core would have impacted A0, A1, A2, A4, A5, A6, and not A3. A middle layer impact has half shock impacts at A0B1, A1B1-A4B1, A5B1.

Below are examples of the different types of impacts. Inside each graph I have lines marking each shock. Red lines are the first half shock while blue is the second half. A black line ends the CME, unless disrupted by another CME or CH. In the top left corner of each image is Coronagraph imagery. In the top right corner of each image is my best estimated line of impact through the CMEs and they do not account for the correct curve of the CME. There is a graph for the CME's IMF, Velocity, and Proton Density.

One of the best CMEs that I know of is a M0 CME that impacted STEREO B on November 8th, 2013. In the image below, the final internal shock is shown as being shock driven with the velocities at A5. All 4 previous internal shocks are seen in the IMF. The line of impact was through the far edge of the A3 shock, where the magnetic field is disrupted, making the central core visible through the IMF data.


An example of an impact through the A3 centr al core shock is a M2 CME that Wind on November 24th, 2001. A sign of this type of impact is when there is a close mirrored IMF shift near A2B1.5 to A3B0.5.


An example of an impact through the edge of the central core, missing the A3 shock, is the CME that hit STEREO A on July 23rd, 2012. This is a M0 CME. A sign of this type of impact is gradual changes of the IMF through A2-A4.


An example of a M2 CME middle layer impact is a CME that impacted ACE on May 23rd, 2002. The IMF remains near constant from A1B1-A4B1 as it runs through the middle layer.


An example of a buckled middle core impact is a M3 CME that impacted STEREO A on September 11th, 2010. This CME is closest to the T-intersections of the central core and middle layers. This may result in a sudden change of the IMF like in the image below. The IMF will also gradually change from A1-A3.


An example of a buckled outer core impact is a M3 CME that impacted ACE on April 11th, 2001. Due to the leading shock extending from A0-A2, there may be some issues with the CME being shock driven. This CME below may have had a little help from behind from another CME. It became shock driven at A3B1-A4 at the end of the buckled middle layer.


An example of a M5 secondary shock impact CME is from Wind on November 10th, 2000. The CME misses the A2 internal shock and becomes shock driven at A2B1-A3.


An example of a M5 far shock impact on DSCOVR is the CME of September 12th, 2017. There isn't much to these impacts. Once the CME passes, there may be a little wall of higher proton density from the solar wind trailing it.


This has gone well beyond where I thought this would lead to and what I have previously posted about, but this post is to close this chapter of my research. I still need to reach the goal of reliable CME arrival time forecasting using my method, so at some point in the future another chapter may begin.

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  • 3 weeks later...

I've shared my up to date method above, but I don't think I have ever actually gone into further detail with imagery examples so I have some created now.

SOHO C3's FOV is near 32Rsun (Field of View near 32 Solar Radii) and the STEREO satellites C2 imagery has a FOV of 15Rsun. In the following images I will show the two coronagraph points in time for using my method. For the STEREO satellites the points in time are estimated to 16Rsun to make the calculations easier to work with. These first two CMEs below have one slide that shows the leading shock in green and secondary shock in red.

I will start out with a M5 CME from STEREO A that launched on August 18th, 2010.

 Launch Time: 2010/08/18 05:52Z
      C P1 Time: 07:40Z
      C P2 Time: 10:30Z
          C Range: 2:50 * 2 (STEREO is multiplied by 2 to use with the current Multiplier's graph)
 C Mean Time: 09:05Z
  Mean Range: 3:13 * 2
     Multiply By: 8.63
Estimated Arrival: 2010/08/20 13:23Z
                   Arrival: 2010/08/20 16:12Z




This CME is from SOHO's imagery on September 10th, 2014.

Launch Time: 2014/09/10 17:38Z
     C P1 Time: 22:30Z
     C P2 Time: 22:30Z
         C Range: 00:00
C Mean Time: 22:30Z
  Mean Range: 4:52
     Multiply By: 8.91
Estimated Arrival: 2014/09/12 13:00Z
                   Arrival: 2014/09/12 15:26Z




This CME from SOHO on September 13th, 2005 has secondary shocks on two sides, but the two coronagraph points are from the leading shock.

 Launch Time: 2005/09/13 20:05Z
      C P1 Time: 22:50Z
      C P2 Time: 07:00Z
         C Range: 8:10
C Mean Time: 02:55Z
  Mean Range: 6:50
     Multiply By: 5.27
Estimated Arrival: 2005/09/15 08:06Z
                   Arrival: 2005/09/15 08:28Z




M0 CMEs like the one that impacted STEREO A on July 23rd, 2012 will have the smallest arrival time offset possible compared to all Multiplies above it.

 Launch Time: 2012-07-23 02:33Z
      C P1 Time: 04:10Z
      C P2 Time: 04:54Z
         C Range: 00:44 * 2
C Mean Time: 04:32Z
  Mean Range: 1:59 * 2
     Multiply By: 4.65
Estimated Arrival: 2012/07/23 20:57Z
                   Arrival: 2012/07/23 20:36Z



These 4 examples are forecasted already knowing the Multiplier. Data sees and gave us the shapes of CMEs, we need to learn to see them too.

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Solar maximums do have the most solar activity, but on the extreme side the possibility of complex sunspot regions resulting in some powerful CMEs may be possible at almost any moment of the solar cycle. There were some CMEs from 2005 and September 2017 nearing solar minimum for examples. At 0.3AU the IMF strength is around 60nT while at 8AU the IMF is down to near 0.5nT and it will keep getting weaker. The MESSENGER satellite made a pass by Earth with with a strength of 20600nT and the Sun's magnetic field will be much stronger.

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  • 2 weeks later...

I did mess around to create a CME model a while back to get the correct curving of the CME structure. I'm not sure that the margin of error is, but it seems fairly close.

This is the CME of September 10th, 2017. The central core is very small leading to a narrow leading shock. STEREO B's C2 imagery most likely would have been M3 or M4 if it was online. Two different preliminary curved structures are below. The orange circle would be the sun and the line intervals are in Rsun.








As well, Merry Christmas, Happy Holidays, and a Happy New Years all.

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  • 2 months later...

This current post is to show without a doubt the structure of Coronal Mass Ejections. On the way of doing this I have learned and updated some information from my first post on this topic.

The Coronal Mass Ejection structure is made of 3 layers, which I call the Central Core, Middle Layer, and Outer Layer. Each of those layers are made of 2 sub-layers and they are separated by what I call a Half Shock. A pass through one layer into another would be an internal shock impact and I call them shocks because CMEs can be shock driven at almost any of them.

I do know that the solar wind can overtake the CME shock by shock. In theory the solar wind IMF will go through first keeping the CME structure intact.

CMEs can take many forms. I call the 3 possible impact regions the Leading Shock, Secondary Shock, and Far Shock. In theory the size of the Central Core determines the size of the Leading Shock. In theory how explosive a CME is determines the size of the Far Shock. Below is an image to show the different forms of the 3 layers.


The evidence of those layers and the forms they create begin here. In the calculations the only number that changes is the travel time. Besides that one number all calculations are exactly the same.

I have graphs of the solar wind and those are the Google Drive links. In each graph the red lines mark the shocks for the 3 main layers and blue lines mark the Half Shocks. The black line is the exit of the outer layer.

I do use abbreviations for shocks and Half Shocks. A# is a shock and B# is a Half Shock. Examples being the span through all layers is A0-A6 and the first half shock is at A0B1.

I have cross sections of most of the CMEs below and those are the Desmos Calculator links. Currently the only use of the model there is to create a close recreation of a cross section of the CME. Blue lines are SOHO's line of impact. Green lines are STEREO A's line of impacts. Red lines are STEREO B's line of impacts. The dotted lines are what I used to help put the cross sections together from coronagraph imagery. The satellite and solar directions from coronagraph imagery are noted next to the links to view and compare. 

Here are graphs where the CME spans from A0 to A6 best visible by velocities, proton density, or the CME being shock driven at A4B1. These are Leading Edge impacts.

CME of April 4th, 2000
This CME is shock driven at A4B1 and ends at A6.
https://www.desmos.com/calculator/txich34nma - SOHO West to East

CME of November 22nd, 2001
This CME is shock driven at A4B1 and ends by A6.
https://www.desmos.com/calculator/4m7ooym9vn - SOHO West to East

CME of March 7th, 2011
This CME is moderately shock driven at A4B1 and ends by A6.
https://www.desmos.com/calculator/nwgwsgc4eb STEREO A Northeast to Southwest

CME of May 17th, 2012
This CME is shock driven at A4B1 and ends at A6.
https://www.desmos.com/calculator/j3ofjrbqhl - STEREO A East to West

CME of July 23rd, 2012
As I created cross sections for these next 2 CMEs my view started changing from what I thought they were like, but they are still CMEs that I know the least about.
https://www.desmos.com/calculator/0yb0rzzoht - STEREO A Northwest to Southeast

CME of November 7th, 2013
This will remain as my favorite CME for a while because all layer shocks are visible in the data. The disruptive IMF ends at A1. The Bt component flips by A2 and is disruptive afterwards. The Bn component flips by A3 for most of the remainder of the CME. The A4 shock impacts and the Bm component begins to decline in intensity. Finally in this case the CME is also shock driven at A5.
https://www.desmos.com/calculator/uozrzabg6x - STEREO B West to East

Here are similar impacts by the Secondary Shock and the CME span is A0 to A4. With that, a CME can be shock driven at A2B1.

CME of February 25th, 2014
This CME is shock driven at A2B1 and ends at A4.
https://www.desmos.com/calculator/mk924awubw - SOHO East to West

CME of November 8th, 2000
This CME is shock driven at A2B1 and ends at A4.

CME of August 18th, 2010
This CME ends at A4.
https://www.desmos.com/calculator/nj8s2tw65p - STEREO A South-Southwest to North-Northeast

CME of January 27th, 2012
Due to the where STEREO A took this impact the CME doesn't have a shock to be shock driven at A2B1.
https://www.desmos.com/calculator/k8hz5jd8co - STEREO A Northeast to Southwest

Now here are some Far Shock CMEs with the span being A0 to A2.

CME of March 7th, 2011https://drive.google.com/open?id=185ClDRWg_9ndnADrmcZv_GYcWuKWiwyf
https://www.desmos.com/calculator/wfgmjuif7r - SOHO Northwest to Southeast

CME of February 25th, 2014
https://www.desmos.com/calculator/mk924awubw - STEREO B West to East

CME of September 10th, 2017
https://www.desmos.com/calculator/wfgmjuif7r - SOHO West to East
https://www.desmos.com/calculator/iusoqzax7n - North to South

Some M3 CMEs are great examples because they can go through a very disrupted magnetic section of the CME. At the A3 shock the IMF has a sudden shift.

CME of September 8th, 2010

CME of June 6th, 2000
https://www.desmos.com/calculator/0rvzrbpc5g - SOHO North to East

CME of March 7th, 2011
https://www.desmos.com/calculator/nwgwsgc4eb - STEREO A  Northeast to Southwest

CME of September 10th, 2014
https://www.desmos.com/calculator/qu9prpdwbb - SOHO North to South

CME of May 6th, 2005
MESSENGER manages to get one of these impacts. The first disruption is when it hits the Half Shock then becomes fully disruptive once it reaches A3.

There are M2 CMEs where there is an impact near the edge. No Secondary Shocks have formed on these sides of the CME. The IMF becomes completely stable, and one thing that I have learned is that the IMF total must remain stable as well. 

CME of May 22nd, 2002
https://www.desmos.com/calculator/2vdjtkjutc - SOHO West-Southwest to East-Northeast

CME of September 13th, 2005
This line of impact is close enough to the edge that the solar wind affected the CME quickly.
https://www.desmos.com/calculator/teqln1ixil - SOHO South-Southeast to North-Northeast

CME of September 6th, 2017
https://www.desmos.com/calculator/xhehoqyyls - SOHO South-Southwest to North-Northeast
https://www.desmos.com/calculator/qi1os6wnm8 - STEREO A West to East

The sheaths can be explained as well. The solar wind effects the CME on all sides including the front shock by shock. The below CMEs sheaths only reach to or overtake A0B1.

CME of July 25th, 2004

CME of January 17th, 2005

CME of May 13th, 2005

CME of November 3rd, 2010

CME of October 10October 10th, 2011

CME of October 14th, 2011https://drive.google.com/open?id=14iq8bPxFULKyVFYTgPPGrsByd08uZ6_m

CME of July 2nd, 2012

CME of July 23rd, 2012

CME of August 19th, 2013

CME of September 10th, 2014

Most of the details of how I came to this point can be seen in the first post of this topic.

Here is where the abbreviation A and B came from along with a C. They are simply from a graphing calculator. This is how I calculate the estimated positions of the Shocks and Half Shocks. t is the travel time, s is the arrival time of the arrival date, and g is any of the shocks to help show the position of each Shock and Half Shock down to the minute. The September 6th, 2017 CME is used as an example.


So there is the structure. This is just the start and there is much more to learn.

The Half Shock goes by the second root. It is possible that more features of each layer will become more detailed going past two.

Knowing which shock/shocks will be strongly shock driven in advanced is unknown, but there are patterns available to tell where they are most likely to be shock driven.

I don't know how many questions there would be on how CMEs overtake other CMEs, but there are several good events to work with.

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  • 8 months later...

I am here with an update. In time I have noticed some mistakes I have made, made some re-calculations, and came to thinking of some overall big factors in play that no one really knows.

A quick summary from the past, M# are what I call Multipliers. It began as a forecasting method, but the main use of it now is using the method in reverse. CMEs can be put into different classes for further study.

Here are the Multipliers' lines of impact. M0 and M1 CMEs have direct impacts of the Leading shock, but on why they exist is an unknown. M2 CMEs a direct impact of the Leading shock. M3 and M5 is actually a range. M3 CMEs have a direct impact of the Leading shock while M5 CMEs have a direct impacts of the Secondary Shock. Between them there is a gradual decline of an unknown span from the Leading shock to the Secondary Shock making impacts of CMEs within the range less reliable for research. There is an unknown decline of the layers within the CME as well.

CMEs having 3 layers and the overall structure is something I will always stand by. I was against the flux rope, but I started thinking if it does exist where is it? A3 is the center of the CME, so searching in that area is the best way to start.

I went through every CME I have in my list and I grouped them by their Multiplier. After going through all of the M2 CMEs, as they are the most reliable Multiplier, I had excluded weak CMEs, CMEs that were disrupted by another trailing CME, and selected the CMEs that were almost a perfect direct hit to the satellite viewing it. That left me with 13 CMEs and 2 pattern variants.

For the graphs coming up next, here are the abbreviations that I use (This may not work for some M3-M5 CMEs). A# is the position of the transition of one layer to another with the leading edge being A0. B# is the the position of the center of a layer and is what I call a Half Shock, an example being the third half shock is at A2B1 (basically only 0 or 1).

In the graphs below the red marker lines are A#, blue is B#, and the purple lines are currently experimental.

Variant 1, at A3 the proton density is at a minimum. Slightly past A3B1 the proton density is at a peak or is rising. In the first 6 links the A3 transition leads to the solar wind or CH HSS. The last 2 links last beyond A4.

https://drive.google.com/file/d/1gRmP8iFR8Dsz8KZSxSeQZAIMR8aZlzxh/view *** This CME does have another CME/CH HSS impact half way through the pattern.


Variant 2, around A3 there is a shock in the solar wind and/or IMF. To note, there are shifts in the total IMF as well with some of the CMEs.


Going back to where is the flux rope if it exists, the center is known. Certainly 13 CMEs doesn't make anything official, though I'd say variant 1 gives its existence a chance. What happens to each individual CME in variant 2 may branch off into another area(s) of research, but I'll leave that for another time.

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This is a very interesting project and the cross sectional analysis of each CME is a novel and detailed way of looking at it. I don't believe there has been many (if any) published studies yet looking into the structure of CMEs to the degree where a cross-section can be made, like you have done. I'm surprised there hasn't been comments on this thread yet too.

Can you confirm that the cross-section is meant to be a front-on view - as if someone would be looking at SOHO/LASCO - as opposed to a top down view like the ENLIL spiral?

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The plane of the cross sections are from the satellite, SOHO, STEREO A, or STEREO B, to the Sun. A few posts up with the desmos graphs I note the plane angle, like northeast to southwest, based on the view in coronagraph imagery.

I do want to note that some things are out of date with what I know at this time. In the first post some of the lines of impact are partially incorrect. Second, my view of CMEs are with them having 3 layers, but it is unknown if all 3 layers are able to wrap around to the the back side center of the CME.

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  • 3 months later...

I have two updates to share today.

As I was building a cross section model Version 3 2021 it brought me to now understand what I call the Multipliers (Read the first post of this topic to know what the Multipliers are). It seems like a duh moment thinking back, but I guess that is progress.

The Multipliers M0 and M1 have been a mystery, but now in a way they no longer exist.

Moving forward the Multiplier labels will be flipped. The old M5 becomes M0, M3 becomes M2, and M2 becomes M3. The new M0 is the maximum Multiplier on the y-axis. The span between M0 to M2 is the transition of the secondary shock to leading shock in the line of impact. The old M0 and M1 are now a span M3+. M3+ CMEs are narrow to very narrow CMEs and there is no set Multiplier for them.

This is the new new Multipliers graph roughly for SOHO's position and C3 FOV.

There are two main factors as to why there are so few M3+ CMEs. One is because they are narrow and the odds of hitting a coronagraph imagery satellite are small. Second to that is they are closer than they appear. The closer they are the duller and harder they become to see through coronagraph imagery.

As the Multipliers are for my forecasting method, I do not know if my method will work with M3+ CMEs. If there is any chance it will come down to the small details within the CME in the coronagraph imagery.


The next update is on Flux Ropes.

I made a run through all SOHO C3 imagery looking for side views of CMEs to help build the new cross section model I am working on. I had the thought to pick out the CMEs with easily visible Flux Ropes and add color coded markers and calculations to them. Those are below.



I do want to make clear of mistakes from previous posts.

The old M6 Multiplier does not exist. In the way I explained it prior the calculations would actually be similar as the old M2.

There are graphs with lines of impact in the top right coroner in this topic. I believe I am correct with some of them, but I have spoken way too soon on others trying to be detailed.

Overall the cross section models need some work. I believe some are on the right path, but certainly not all of them. The new cross section model does solve some of the issues.

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  • 2 months later...

I had some STEREO A data issues so maybe more will be added later... Currently I now have a complete list of 84 CME flux ropes.

Brief info, SOHO and both STEREO satellite's coronagraph imagery are used. In each image I have markers placed centered in the middle of the flux rope. The markers are placed based on theoretical calculations based on facts given from the leading structure of a CME.

The images can be found below,

It might take a while to go through them all, but I'd be grateful for any feedback. 

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  • 2 months later...

Your project and the detailed analysis contained herein is fascinating. 

It has answered a few questions I had.

You made a point that narrow CME's may not be picked by satellites. Is it still the case or have satellites improved? 

I notice even now predictions of the arrival of CME's are often way off. Have you come any closer to being able to predict them?  

Often when a CME is predicted to give a glancing blow, it doesn't eventuate. Have you undertaken any research that would predict the passage of CME's when solar flares are not directly Earth facing? 

It would be great to hear of any follow up work you have done.:)


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Narrow CMEs would be the same as all other CMEs, the visibility of each in coronagraph imagery varies per CME. The satellites with coronagraph imagery, SOHO has been in use for around 25 years and STEREO A has been in use for around 14 years being the latest. An improved satellite would be great.

My CME arrival time prediction method is still in it's early stages. M0 CMEs(check my first post on February 17th) through coronagraph imagery most of the time has a very distinct look. Realistically those are the only CMEs I can forecast because I know what they are. With that said my M0 predictions have ended up having near the same time of error as the SWPC WSA-ENLIL model, but the lead time far exceeds the models.

For a glancing blow a full halo in the coronagraph imagery is required, even if one side is there just by a little bit. The CME can be anywhere on our visible solar disk, though if it is on a limb it needs to be checked to see if it is on the other side of the Sun. If a CME doesn't arrive then the solar wind may have removed an unknown amount of it, or another CME ran it over and hit us first.

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Appreciate your reply Jesterface 23.

I did go back and check your early posts, I understand what you are saying about the distinctive structure of the M0 CME's but this a good base from which you can continue your research.

Yeah I agree, time to get satellite upgrade. I notice when Stereo B was in operation it was sensing output from the sun slightly differently to that of Stereo A. Pity we dont have access to that extra pair of eyes anymore!

The cross-section diagrams and structure of CME's I found very interesting. 

Solar wind pushing the CME aside. It's obvious now you mention it. 

Thanks again :)


Edited by Newbie
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Looked pretty big starting at 2021-JUL-15-2200.   Full halo and a strong streaming southward component.  Stereo coronographs might yield some additional information, if they're not too noisy.

Update - SWPC forecast discussion mentions the event, but with no expected Earth impact, no further estimation of strength or other characterization of it:

":Product: Forecast Discussion

:Issued: 2021 Jul 16 1230 UTC

A DSF was observed in the NE quadrant at the end of 15 Jul. Subsequent coronagraph imagery from L1 was dominated by a halo CME event that took place on the far side of the Sun just prior to the DSF. Available coronagraph imagery from STEREO-A COR 2 contains a gap during the event. Despite the suboptimal imagery, there does not appear to be any clear indication of a CME component along the Sun-Earth line"

Edited by Drax Spacex
added SWPC forecast discussion
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I am a newbie and find your research very interesting, fascinating  and educational.  Do you have some kind of degree in physics?  

I have been following space weather for quite some time.  But I have been doing it because I found some kind of connection with the solar activity and the effects on insects, birds animals and humans.  I have absolutely no higher education than high school from the 70's so don't know much, just what I have observed.  what part of the united states are you located?



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I'm the same as you, just up to high school. I am someone that gained an interest in space weather and it hasn't left. The part of the US I am in, I'd most likely need high K8 or K9 to see the aurora.

As you read through my topic keep in mind this is research. Not all of it is set in stone.

I think your area of interest has come up somewhere in the forums, but I can't exactly remember where.

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