AR 13341

[Philalethes]

First X-flare in a while from the region on the limb. Looks like there was some eruptivity, but it's difficult to say for sure how much. This was the region that looked promising on the farside imagery for a while lately, let's see if it can keep up.

[mozy]

Lol just how.. Looks like there's barely even anything there

[Calder]

This region looks so wimpy right now and of course it lets out an X flare on the limb. 😂

[Philalethes]

13 minutes ago, mozy said:

Lol just how.. Looks like there's barely even anything there

[MinYoongi]

 

16 minutes ago, mozy said:

Lol just how.. Looks like there's barely even anything there

i observed an M-Class from a plage once 🤷‍♀️

20 minutes ago, Philalethes said:

 This was the region that looked promising on the farside imagery for a while lately, let's see if it can keep up.

Do you have screenshots or days i can look up? I was kinda busy the last few days and didnt check farside stuff  

[Philalethes]

9 minutes ago, MinYoongi said:

Do you have screenshots or days i can look up? I was kinda busy the last few days and didnt check farside stuff  

I did make a post about it here, actually, with the latest GONG imagery, after 3gMike noted that we'd be expecting an AR; but you never know exactly what to expect, some of those regions die out before you ever even see them, while others...well, bring X-flares.

[MinYoongi]

is there a glancing blow chance?

[Sam Warfel]

Cool to see a nice eruptive X-flare, been a while! Even if it on the limb, at least it’s the limb of hope! That 1000km/s Type II is nice 

[SpaceWeather5464]

1 hour ago, MinYoongi said:

is there a glancing blow chance?

If you look at SDO AIA 211 it looks like a small part of the CME is heading our way.

[Jesterface23]

I'd have a preliminary arrival time at SA of 2023/06/23 08:15Z at around 63 hours travel time. Not expecting much for Earth, given a glancing blow and maybe 3 days of travel time. 

[Philalethes]

3 hours ago, SpaceWeather5464 said:

If you look at SDO AIA 211 it looks like a small part of the CME is heading our way.

I tried making something out there, but couldn't quite spot what you mean. On C3 I think I can make out some very faint parts of the eruption extending past 180°, but I might just be deluding myself.

[Calder]

6 hours ago, Philalethes said:

I tried making something out there, but couldn't quite spot what you mean. On C3 I think I can make out some very faint parts of the eruption extending past 180°, but I might just be deluding myself.

I think what they’re pointing out on AIA 211 is more visible when looking at the dimming here:

https://www.sidc.be/solardemon/dimmings.php?science=0&did=6789

This actually runs on SDO AIA 211 data. You can see the wave travel across to the west (right).

[Philalethes]

2 hours ago, Calder said:

I think what they’re pointing out on AIA 211 is more visible when looking at the dimming here:

https://www.sidc.be/solardemon/dimmings.php?science=0&did=6789

This actually runs on SDO AIA 211 data. You can see the wave travel across to the west (right).

Oh yeah, I did notice the dimming; but I'm still not sure if there's much of an indication there of anything headed our way. Seems to me like most of the dimming occurred in the other direction too. But could be a glancing blow, maybe.

[Ester89]

Could someone explain to me in a simple way what the dimming is and how can I see it? 

[Philalethes]

49 minutes ago, Ester89 said:

Could someone explain to me in a simple way what the dimming is and how can I see it? 

Certainly. If you look at e.g. coronal holes, you will see that they look quite dark, because the corona (essentially the Solar "atmosphere") is less dense there; the bright light you typically see emitted from it is the plasma being highly ionized and emitting light, so when there is less plasma there is less light, hence why it looks darker. Note that here I'm using "light" to refer to the high-frequency electromagnetic waves shown in the imagery that are mostly outside of the visible spectrum, rather than visible light, just to clarify (that being said, the corona is also visible to the naked eye, and can be seen directly during Solar eclipses).

So in the case of CMEs, a chunk of the corona is what's being ejected (hence the name, coronal mass ejection), leading to the same effect to varying degrees, a darkening due to there being less plasma left, i.e. "dimming". In the most extreme cases the resulting dimming can even match that of coronal holes (as was discussed briefly a few months ago here).

The link Calder provided above is essentially a tool that tries to automatically detect how much dimming there is and where it occurs, in order to estimate how much mass was ejected and in what direction(s).

Hope that helps.

Edited June 21, 2023 by Philalethes
clarification

[Calder]

2 hours ago, Philalethes said:

Oh yeah, I did notice the dimming; but I'm still not sure if there's much of an indication there of anything headed our way. Seems to me like most of the dimming occurred in the other direction too. But could be a glancing blow, maybe.

I agree, I think we’ll only see a slight glancing blow at best.

[Newbie]

2 hours ago, Ester89 said:

Could someone explain to me in a simple way what the dimming is and how can I see it?

Dimming, in the context of a coronal mass ejection (CME) being released, refers to a decrease in the brightness or intensity of certain regions on the Sun's surface, specifically in the solar corona. The solar corona is the outermost layer of the Sun's atmosphere.

During the buildup of a CME, the Sun's magnetic field lines become twisted and unstable. As a result, large amounts of energized particles, plasma, and magnetic fields are expelled from the Sun's surface and ejected into space. This expulsion is known as a CME.

Prior to the actual ejection of a CME, astronomers and scientists observe a phenomenon called dimming. It is characterized by a decrease in brightness or intensity of the regions on the Sun's surface where the CME is forming. This dimming occurs because the ejected material obscures or blocks the light emitted by the underlying region.

Dimming can be detected using various observational techniques, such as specialized instruments that capture different wavelengths of light emitted by the Sun. By monitoring and analyzing these changes in brightness, scientists can track the development and progression of a CME.

Overall, dimming provides valuable information about the dynamics and initiation of a CME, allowing scientists to better understand and predict space weather events that can affect Earth and other celestial bodies.

N.

[Philalethes]

26 minutes ago, Newbie said:

This dimming occurs because the ejected material obscures or blocks the light emitted by the underlying region.

I'm pretty sure the primary reason for dimming is the resulting absence of plasma in the corona rather than regions being obscured by the ejecta, at least based on what I've read and my understanding of it. See e.g. this paper:

Quote

Coronal “dimming” is one of the main on-disk signatures of a CME. When originally discovered during the Skylab era they were called “transient coronal holes” (e.g., Rust 1983). Coronal dimming characteristics suggest they are due to a loss of coronal plasma. Sterling and Hudson (1997) showed a very clear example of dimming using data from the Soft X-ray Telescope on Yohkoh. These dimmings persisted for three days following the flare and related halo CME. In this case it was suggested that the dimmings were consistent with the source of the CME being a flux rope that erupted leaving behind the dimming regions.

Or this one:

Quote

When extreme ultraviolet (EUV) emitting material in the corona is lost during a coronal mass ejection (CME), the solar spectral irradiance is impacted and these effects are observed in data from the Solar Dynamics Observatory (SDO) EUV Variability Experiment (EVE) and Atmospheric Imaging Assembly (AIA). This process is one of the physical mechanisms that can lead to the observation of 'coronal dimming,' a phenomenon lasting eight hours on average and rarely persisting longer than one day.

Or here:

Quote

The temporal and spatial evolution of dimming in multiple wavelengths suggests that dimming in these regions is not caused by thermal dimming or disruption of pre-flare active region loops (Harra et al., 2011; Hock et al., 2010), neither do they appear to be obscured by absorptive materials. Most likely, dimming is caused by density decrease due to expansion of corona structures anchored at these locations.

This makes the most sense to me too given what I've observed and some of the previously mentioned facts. Less material to be highly ionized and thus emit radiation would naturally lead to dimming.

[_00_]

maybe this help too about dimming: https://arxiv.org/pdf/2209.05982.pdf

 

Quote

Inter-Correlation Between Sunspot Oscillations and Their Internal Structures
Research in Astronomy and Astrophysics manuscript no.
(LATEX: main.tex; printed on September 14, 2022; 0:40)
Libo Fu1, Zizhan Zhu1, Ding Yuan1?, Jiaoyang Wang1, Song Feng2 and Sergey Anfinogentov3
1 Institute of Space Science and Applied Technology, Harbin Institute of Technology, Shenzhen 518055,
China; *****@*****.com
2 Faculty of Information Engineering and Automation, Kunming University of Science and Technology,
Kunming 650500, China
3 Institute of Solar-Terrestrial Physics SB RAS, Lermontov st. 126a, 664033, Irkutsk, Russia

 

Abstract:

Three- and five-minute oscillations are commonly found in any sunspot. As they are modulated by the internal thermal and magnetic structures of a sunspot, there hence, they could be used as an effective tool for sunspot seismology. In this paper, we investigate the properties of oscillations in sunspot groups with varying size and magnetic field, and aim to establish the relationships between sunspot oscillations and its internal structure comparatively. We selected three groups of unipolar sunspot with approximately axial-symmetric magnetic field and calculated their Fourier spectra based on the Ultraviolet(UV)/Extreme ultraviolet(EUV) emission intensity variations recorded by the Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA). We found that the distribution of three minute oscillation is defined by the joint effect of diverging magnetic field and the stratification of sunspot atmosphere. Its distribution could be modified by any invading magnetic structures in the umbra. Whereas the five minute oscillations are more prominent in small spots, it implies that five minute oscillation is very closely connected with umbral dynamics.

 

Edited June 21, 2023 by _00_

[Philalethes]

23 minutes ago, _00_ said:

maybe this help too about dimming: https://arxiv.org/pdf/2209.05982.pdf

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. 

[Ester89]

@Philalethes @Newbie Thank you very much for taking the time in your answer

7 hours ago, Philalethes said:

Certainly. If you look at e.g. coronal holes, you will see that they look quite dark, because the corona (essentially the Solar "atmosphere") is less dense there; the bright light you typically see emitted from it is the plasma being highly ionized and emitting light, so when there is less plasma there is less light, hence why it looks darker. Note that here I'm using "light" to refer to the high-frequency electromagnetic waves shown in the imagery that are mostly outside of the visible spectrum, rather than visible light, just to clarify (that being said, the corona is also visible to the naked eye, and can be seen directly during Solar eclipses).

So in the case of CMEs, a chunk of the corona is what's being ejected (hence the name, coronal mass ejection), leading to the same effect to varying degrees, a darkening due to there being less plasma left, i.e. "dimming". In the most extreme cases the resulting dimming can even match that of coronal holes (as was discussed briefly a few months ago here).

The link Calder provided above is essentially a tool that tries to automatically detect how much dimming there is and where it occurs, in order to estimate how much mass was ejected and in what direction(s).

Hope that helps.

With this explanation I come to the conclusion that the dimming occurs after the CME

5 hours ago, Newbie said:

Dimming, in the context of a coronal mass ejection (CME) being released, refers to a decrease in the brightness or intensity of certain regions on the Sun's surface, specifically in the solar corona. The solar corona is the outermost layer of the Sun's atmosphere.

During the buildup of a CME, the Sun's magnetic field lines become twisted and unstable. As a result, large amounts of energized particles, plasma, and magnetic fields are expelled from the Sun's surface and ejected into space. This expulsion is known as a CME.

Prior to the actual ejection of a CME, astronomers and scientists observe a phenomenon called dimming. It is characterized by a decrease in brightness or intensity of the regions on the Sun's surface where the CME is forming. This dimming occurs because the ejected material obscures or blocks the light emitted by the underlying region.

Dimming can be detected using various observational techniques, such as specialized instruments that capture different wavelengths of light emitted by the Sun. By monitoring and analyzing these changes in brightness, scientists can track the development and progression of a CME.

Overall, dimming provides valuable information about the dynamics and initiation of a CME, allowing scientists to better understand and predict space weather events that can affect Earth and other celestial bodies.

N.

And here I understand that the dimming would occur before the CME.

 

Anyway, I think I have the gist of what "dimming" is 😀

[Newbie]

4 hours ago, Ester89 said:

@Philalethes @Newbie Thank you very much for taking the time in your answer

With this explanation I come to the conclusion that the dimming occurs after the CME

And here I understand that the dimming would occur before the CME.

 

Anyway, I think I have the gist of what "dimming" is 😀

The take away really is that dimming is indicative of CME activity.
 

@Philalethes

Coronal dimming typically occurs before a coronal mass ejection (CME) is launched. Coronal dimming refers to the temporary decrease in intensity of certain regions in the solar corona, which are associated with the release of plasma and magnetic fields during a CME event. It is often observed as darkening or reduction in the brightness of the affected areas in extreme ultraviolet (EUV) or X-ray observations of the Sun.

The process of coronal dimming is believed to be a result of the CME's magnetic fields lifting and carrying away the surrounding coronal material. As the CME begins to form and build up energy, it disturbs the equilibrium of the coronal plasma and causes it to expand outward, leading to a decrease in the observed intensity.

Observing coronal dimming can be an indicator that a CME is about to occur. 
N.

[Jesterface23]

4 minutes ago, Newbie said:

Coronal dimming typically occurs before a coronal mass ejection (CME) is launched.

It comes to when is the CME considered "Launched"

[Philalethes]

27 minutes ago, Newbie said:

The take away really is that dimming is indicative of CME activity.
 

@Philalethes

Coronal dimming typically occurs before a coronal mass ejection (CME) is launched. Coronal dimming refers to the temporary decrease in intensity of certain regions in the solar corona, which are associated with the release of plasma and magnetic fields during a CME event. It is often observed as darkening or reduction in the brightness of the affected areas in extreme ultraviolet (EUV) or X-ray observations of the Sun.

The process of coronal dimming is believed to be a result of the CME's magnetic fields lifting and carrying away the surrounding coronal material. As the CME begins to form and build up energy, it disturbs the equilibrium of the coronal plasma and causes it to expand outward, leading to a decrease in the observed intensity.

Observing coronal dimming can be an indicator that a CME is about to occur. 
N.

Yeah, I think that is more or less what I'm saying, i.e. that the expansion and subsequent ejection of the coronal mass, and thus the remaining lower density, is what causes the dimming. Whether or not the dimming starts happening "before" the ejection or not is a matter of definition I suppose, since it starts occurring as the plasma expands as part of the ejection process, which is also why you typically see most of the dimming occur as and after the mass is ejected, and why the dimming typically persists for many hours afterwards, even days in some cases. This is also what the papers mentioned above argue. But I do understand what you are saying and what you mean by "before", i.e. that it starts happening before the mass has actually been fully ejected, and I do agree with that; my point wasn't so much when exactly the dimming can be said to begin, but that it's not really caused by the ejected material obscuring the corona below, instead being caused primarily by the low density of plasma left behind. I essentially agree with everything you stated in that post except for that claim.

28 minutes ago, Jesterface23 said:

It comes to when is the CME considered "Launched"

Yeah, exactly. I think it's fair to say, as per the above, that while some initial dimming will indeed occur as the plasma starts expanding before there's been what you'd typically call the ejection, the majority of the dimming will occur after the ejection takes place, since that's when most of the mass is lost, leaving behind a significant "hole" (the infamous "transient coronal hole") and lower density regions dragged out from the surrounding areas, which will then proceed to equilibrate over the next hours (or days in extreme cases) as plasma from the surrounding corona moves in to fill the gap.

[Newbie]

1 hour ago, Jesterface23 said:

It comes to when is the CME considered "Launched"

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.