AR 13341

[Jesterface23]

10 minutes ago, Newbie said:

Coronal dimming is often associated with the launch of a coronal mass ejection (CME), but it is not an immediate precursor. Instead, coronal dimming is a phenomenon that occurs before the CME eruption.

Coronal dimming refers to a decrease in the intensity of extreme ultraviolet (EUV) and X-ray emissions from the solar corona. It appears as darkened regions in images of the Sun's atmosphere. This dimming occurs because material in the corona is being ejected into space during the CME event.

The process leading to a CME typically involves the destabilization and eruption of a magnetic structure within the solar corona, such as a coronal prominence or a twisted magnetic flux rope. As this magnetic structure becomes unstable, it releases a large amount of energy, causing the surrounding material to be expelled into space as a CME.

Coronal dimming is observed as the evacuated material from the corona moves away from the Sun, creating a darker region. This dimming can be observed in EUV and X-ray wavelengths before the actual CME is fully launched.

So, to summarize, coronal dimming occurs before the launch of a CME, indicating that the process of CME formation and eruption is underway.

N.

We'll need a new topic opened on this. Imagery examples would be great as well.

[_00_]

7 hours ago, Philalethes said:

I don't see how that's related to coronal dimming at all. That paper is talking about something entirely different and virtually unrelated to dimming. 

it's about sunspot dimming, but yes, not coronal dimming related.

[Jesterface23]

Another nice M-Class flare. There was a little filament hanging around the region, so I wonder if that would launch.

[MinYoongi]

9 minutes ago, Jesterface23 said:

Another nice M-Class flare. There was a little filament hanging around the region, so I wonder if that would launch.

Please update us. Maybe a bit glancing blow Chance based on the location?

[Jesterface23]

1 minute ago, MinYoongi said:

Please update us. Maybe a bit glancing blow Chance based on the location?

It is an eruptive event with a CME launched. We are only a few images in right now, so hard to tell if it is decent

[MinYoongi]

9 minutes ago, Jesterface23 said:

It is an eruptive event with a CME launched. We are only a few images in right now, so hard to tell if it is decent

Okay. Solarham said it’s mostly south.

That’s why I’m asking. I’m outside rn, so can’t check too thoroughly.

„So far most of the plasma appears to be headed to the south, however coronagraph imagery will be required to confirm this. Stay tuned.“

[mozy]

I guess this is gonna be one of those regions that look like nothing but continously produce bigger flares somehow.

[MinYoongi]

5 minutes ago, mozy said:

I guess this is gonna be one of those regions that look like nothing but continously produce bigger flares somehow.

It really looks like nothing. i wonder where the flare came from, lol! I looked at it when i saw the flare and to me it almost looked like an alpha sunspot.

[Jesterface23]

An unnumbered region to the east is reverse polarity if that adds any more confusion to the area

[MinYoongi]

2 minutes ago, Jesterface23 said:

An unnumbered region to the east is reverse polarity if that adds any more confusion to the area

what do you mean with "any more confusion to the area" ? Maybe a little bit language barrier right now. i dont think theyre close enough to influence each other

if thats what you meant

 

[Jesterface23]

4 minutes ago, MinYoongi said:

what do you mean with "any more confusion to the area" ?

Just random stuff happening within a relatively small area

[cgrant26]

1 hour ago, Jesterface23 said:

It is an eruptive event with a CME launched. We are only a few images in right now, so hard to tell if it is decent

Just a few frames at the end of the SDO daily movies for June 22nd.

https://sdo.gsfc.nasa.gov/data/dailymov/movie.php?q=20230622_1024_0094

Interesting that this last one popped out of this part:

 

 

[Jesterface23]

Hopefully SOHO isn't down. There is at least an asymmetric halo SA's differenced C2 imagery.

.........

Aaaand it is back up

Edited June 23, 2023 by Jesterface23

[ChefyStephie]

8 hours ago, Jesterface23 said:

Hopefully SOHO isn't down. There is at least an asymmetric halo SA's differenced C2 imagery.

.........

Aaaand it is back up

I’ve noticed SOHO going quiet periodically. Doesn’t seem to be a long time when it happens, just enough for some accidental cardio (elevated heart rate). And the STEREO website is sometimes “clunky”. 
 

Difficult to ascertain if it’s Earth base tech issues, or if the old girl is struggling. I haven’t seen any news releases, but I do know SOHO’s funding is approve through 2025 (so for at least the period of this solar max). She’s taken a beating up there for a long time, but she presents the most pleasing images, so hopefully it’s just funkiness on our end.

[Philalethes]

31 minutes ago, ChefyStephie said:

I’ve noticed SOHO going quiet periodically. Doesn’t seem to be a long time when it happens, just enough for some accidental cardio (elevated heart rate). And the STEREO website is sometimes “clunky”. 
 

Difficult to ascertain if it’s Earth base tech issues, or if the old girl is struggling. I haven’t seen any news releases, but I do know SOHO’s funding is approve through 2025 (so for at least the period of this solar max). She’s taken a beating up there for a long time, but she presents the most pleasing images, so hopefully it’s just funkiness on our end.

SOHO is definitely very old, but its mission has indeed been extended. Quite interesting development after its near loss and incredible recovery effort only 2.5 years into its mission, as it has now been operational for almost 30 years.

As for why it periodically goes quiet it's hard to tell the exact reason, but I remember last time it was discussed that I read something about how data from it is relayed via the Deep Space Network, and that there are a variety of other craft and missions competing for usage of that network, many of which are typically prioritized over it due to its age. I think I've noticed that it happens more often when there are events of interest, although it could be some form of bias on my part since I check it more often during those times; but it could also be explained by other craft being prioritized for communication during such events too.

Certainly something that could be looked more into, but there will also soon be a new craft dedicated to coronagraphy in Aditya, which is set to launch in a couple of months; I hope all goes well with that and that there will be regularly updated public data for us to watch from it. If so I could see SOHO finally being retired after 2025, but it might be kept around anyway if it's still working alright.

[Jesterface23]

There's some good news and bad news with the latest CME. Good news, we might get a bulk hit. Bad news, it's slow.

[Philalethes]

1 hour ago, Jesterface23 said:

There's some good news and bad news with the latest CME. Good news, we might get a bulk hit. Bad news, it's slow.

How do you figure? I can't say I see much from C3 at least, but I haven't looked at any other imagery so far.

Even a slow CME could bring some geomagnetic activity given the high density I guess, and if I recall correctly slow CMEs are more likely to be deflected towards Earth if launched from the "eastern" part of the disc too.

[Jesterface23]

6 minutes ago, Philalethes said:

How do you figure?

It is a very faint CME, even in difference imagery. It looks to be a full halo CME.

This CME may not have a travel time too far off of the previous CME, if the previous CME hit SA a few hours ago.

15 minutes ago, Philalethes said:

if I recall correctly slow CMEs are more likely to be deflected towards Earth if launched from the "eastern" part of the disc too.

The parker spiral may help bring western disk CMEs further east. Not sure if we are thinking the same thing though

[Philalethes]

15 minutes ago, Jesterface23 said:

It is a very faint CME, even in difference imagery. It looks to be a full halo CME.

This CME may not have a travel time too far off of the previous CME, if the previous CME hit SA a few hours ago.

The parker spiral may help bring western disk CMEs further east. Not sure if we are thinking the same thing though

What difference imagery are you looking at? Using Helioviewer? I've seen people publish some videos of such imagery, but haven't found it myself, so I figured they're using that or other tools to generate it.

And I see the disturbance you're referring to in the SA Solar wind data, fits very well with what you predicted.

As for the deflection I'm talking about it's from this paper, which details how CMEs from various positions will typically be deflected based on their speed. From the abstract:

Quote

A solar coronal mass ejection (CME) is a large-scale eruption of plasma and magnetic fields from the Sun. It is believed to be the main source of strong interplanetary disturbances that may cause intense geomagnetic storms. However, not all front-side halo CMEs can encounter the Earth and produce geomagnetic storms. The longitude distribution of the Earth-encountered front-side halo CMEs (EFHCMEs) has not only an east–west (E–W) asymmetry (Wang etal., 2002), but also depends on the EFHCMEs'' transit speeds from the Sun to 1AU. The faster the EFHCMEs are, the more westward does their distribution shift, and as a whole, the distribution shifts to the west. Combining the observational results and a simple kinetic analysis, we believe that such E–W asymmetry appearing in the source longitude distribution is due to the deflection of CMEs'' propagation in the interplanetary medium. Under the effect of the Parker spiral magnetic field, a fast CME will be blocked by the background solar wind ahead and deflected to the east, whereas a slow CME will be pushed by the following background solar wind and deflected to the west. The deflection angle may be estimated according to the CMEs'' transit speed by using a kinetic model. It is shown that slow CMEs can be deflected more easily than fast ones. This is consistent with the observational results obtained by Zhang etal. (2003), that all four Earth-encountered limb CMEs originated from the east. On the other hand, since the most of the EFHCMEs are fast events, the range of the longitude distribution given by the theoretical model is E40,W70, which is well consistent with the observational results (E40,W75).

The first part in bold there is likely what you're thinking of, which is what's typically relevant for faster CMEs that tend to be more interesting; fast CMEs will indeed tend to be deflected towards "east", hence why their distribution is shifted "west". The second part in bold mentions how the opposite is the case for slow CMEs, which will insted be deflected in the other direction. And in the last part is mentioned how slow CMEs are actually more readily deflected than faster ones, and how all the CMEs they looked at that both originated from the limb and hit Earth came from the "eastern" limb.

I thought that was very interesting when I read it, so now I try to be on the lookout for slow halo CMEs that originate from the "eastern" limb.

Addendum to illustrate the modeled deflection angle as per the plot in the paper:

[Jesterface23]

8 minutes ago, Philalethes said:

What difference imagery are you looking at? Using Helioviewer?

I use JHelioviewer. Helioviewer is online and JHelioviewer can be downloaded.

11 minutes ago, Philalethes said:

As for the deflection I'm talking about it's from this paper, which details how CMEs from various positions will typically be deflected based on their speed. From the abstract:

Pretty interesting

[Philalethes]

6 minutes ago, Jesterface23 said:

I use JHelioviewer. Helioviewer is online and JHelioviewer can be downloaded.

Pretty interesting

I see; I never ended up downloading that as I just used the online version instead, but maybe it's time to check it out.

And yeah, it's definitely interesting, I added the chart where they sum up the deflection angle at 1 au based on the average transit speed too, it's quite neat. If your estimate is 63 hours again, that comes out as an average transit speed of ~660 km/s, which according to the chart should yield a negative deflection angle rather than a positive one. In other words, what they term "slow" isn't slow enough for the positive deflection angle I was hoping for when you said it would likely be slow, as it'd have to be slower than ~450 km/s (at which point the deflection angle is 0°) for that to happen.