The Coronal Heating Problem - The Hydrogen Fusion Core disappears?

[Gfellow]

TL;DR Summary

Edits in Wikipedia "The Coronal Heating Problem" appear to have removed the Hot Hydrogen Fusion Core as part of the problem?

In previous manifestations explaining the Coronal Heating Problem, scientists pointed out the discontinuity between a very hot Solar interior, the 'cool' Photosphere and a Hot Corona.
According to the newly modified entry in Wikipedia, they now explain the discontinuity only between a cool Photosphere and a Hot Corona.
No Solar interior.
Am I missing something?
Please let me know if I've got this wrong; I do have a slight dyslexia problem.

https://en.wikipedia.org/wiki/Stellar_corona#Coronal_heating_problem

 

[Drakkith]

I'm not sure why the interior details matter that much, except in so much as they might allow energy transfer via non-thermodynamic processes. The temperature discontinuity isn't between the corona and the interior, it's between the corona and the photosphere after all.

 

[davenn]

Summary:: Edits in Wikipedia "The Coronal Heating Problem" appear to have removed the Hot Hydrogen Fusion Core as part of the problem?

No Solar interior.
Am I missing something?

yes, you are.
The core doesn't have much to do with the heating of the corona ( no direct link)
The recent findings ( last few years) hint that the heating is a result of flaring and transport of energy by magnetic fields

here's 3 sites to get you started, I'm sure you can delve deeper :)
https://phys.org/news/2019-09-solar-corona.html

https://science.nasa.gov/news-articles/the-mystery-of-coronal-heating

https://www.sciencedirect.com/science/article/abs/pii/016779779090011TDAve

 

[Gfellow]

Thanks for the reply and links.
Isn't it a little like taking note of the heat coming from a stove in a winter cabin, musing as to why the stove is cool, the room is warm - and ignoring the interior heat of the stove?

 

[Drakkith]

Isn't it a little like taking note of the heat coming from a stove in a winter cabin, musing as to why the stove is cool, the room is warm - and ignoring the interior heat of the stove?

It's more like asking how the air just above the stove's surface is getting heated and ignoring the details of how the wood burns, as it isn't relevant. Exactly how the heat is transferred from the solar core to the upper layers isn't really important. It's about how the upper layers transfer heat to the corona.

 

[Gfellow]

Isn't really important? A whopping great solar core furnace?
The magnitude temperatures such as these are hard for me to grasp, so I created this model to help me understand the problem:
Let’s pretend we can drop the temperature of the Photosphere to 0 Degrees Celsius so this shell is the temperature of a snowball:

Then let us drop the temperatures of the inner core and outer atmospheric Corona in proportion: What one ends up with are exceedingly high temperatures from the solar core and high temperatures in the Corona - with a snowball shell sandwiched in between:

Sandwiched between this snowball shell, the core would be 2,700 C - hot enough to melt steel - and the atmospheric Corona would have a temperature that varies from 180 C to 1,800 C - a temperature so hot that you if were standing in the vicinity of this temperature-dropped snowball, you would either parboil or vaporize.

The above image was taken from Wikipedia's page 'The Coronal heating problem' a year ago. It has now disappeared.
Is there something that has recently occurred in solar science that I am unaware of?

 

[Drakkith]

The above image was taken from Wikipedia's page 'The Coronal heating problem' a year ago. It has now disappeared.

So? Wikipedia editors do their own thing.

Isn't really important? A whopping great solar core furnace?

Nope. Don't get me wrong. It's obviously important in the grand scheme of understanding how stars function, but the details of core fusion are not always important when you're trying to understand a specific aspect of a star. Especially on small time scales.

Sandwiched between this snowball shell, the core would be 2,700 C - hot enough to melt steel - and the atmospheric Corona would have a temperature that varies from 180 C to 1,800 C - a temperature so hot that you if were standing in the vicinity of this temperature-dropped snowball, you would either parboil or vaporize.

Well, if we scale things like you said, you'd probably be okay thanks to the extremely low density of the snowball-corona.

 

[DrStupid]

It's about how the upper layers transfer heat to the corona.

As heat flows from hot to cold by definition, the colder upper layers cannot transfer heat to the hotter corona. There is energy transferred to the corona, but if it comes from the upper layers it is not heat.

It has already been mentioned before that there is energy transport by magnetic fields involved. Leaving the core out of the discussion would require that it has no significant impact on the generation of these magnetic fields. Is that the case?

 

[Drakkith]

As heat flows from hot to cold by definition, the colder upper layers cannot transfer heat to the hotter corona. There is energy transferred to the corona, but if it comes from the upper layers it is not heat.

Indeed. I didn't think anyone would catch my little slip there. Shoulda known better.

It has already been mentioned before that there is energy transport by magnetic fields involved. Leaving the core out of the discussion would require that it has no significant impact on the generation of these magnetic fields. Is that the case?

I believe so. The core is obviously important in keeping the interior of the Sun hot, but beyond that I don't think it matters for understanding how the corona gets heated. If all fusion in the core ceased right now the Sun would still appear to function normally for years and years.

 

[Gfellow]

Just seems myopic, ignoring the elephant in the room, a 15 million C solar core, that no one has as yet discovered a venting solution for heat dissipation.
Divorcing the Corona from the Photosphere and the core makes a mockery of the Coronal heating problem - the 2nd law of Thermodynamics - hot, through cold, to hot; it's a cop-out to what should be an intriguing and challenging problem.
Wikipedia is a major referencing tool for millions of people. Disengaging the Core altogether from the Coronal Heating Problem is disturbingly disappointing to say the least.
But if nobody else is bothered, I'll let the subject drop.

 

[Drakkith]

Just seems myopic, ignoring the elephant in the room, a 15 million C solar core, that no one has as yet discovered a venting solution for heat dissipation.

What are you talking about? The heat dissipation is almost entirely due to radiated EM radiation from the photosphere, with heat being transferred from the core via convection and radiation transfer. This is trivial.

Divorcing the Corona from the Photosphere and the core makes a mockery of the Coronal heating problem - the 2nd law of Thermodynamics - hot, through cold, to hot; it's a cop-out to what should be an intriguing and challenging problem.

No one has divorced it from the photosphere. And no one has really divorced it from the core either. The core provides the heat that keeps the photosphere and other outer layers hot, and it is these hot layers of plasma that determine how the corona is heated.

It's quite simply that the details of fusion don't really matter when we look into how the corona is heated. If fusion ceased in the core the Sun would still behave normally for millennia, as it has an enormous amount of thermal energy in its huge mass and would still be heated by gravitational contraction. So you'd still have a very hot core that transitions to lower temperature outer layers with a surrounding corona.

And I'll say once again that time and distance scales matter here. Both dominant heating theories, magnetic reconnection and wave heating theory, take place on short time scales and are confined to the upper layers. NOTHING in the core will affect this, as changes to the core take a very long time to propagate outward and are typically constrained to relatively small temperature and density fluctuations that don't drastically change anything.

Wikipedia is a major referencing tool for millions of people. Disengaging the Core altogether from the Coronal Heating Problem is disturbingly disappointing to say the least.

Not if it doesn't matter that the two are 'disengaged'.

 

[Vanadium 50]

Isn't it a little like taking note of the heat coming from a stove in a winter cabin, musing as to why the stove is cool, the room is warm - and ignoring the interior heat of the stove?

It's more like taking note of the heat in the room from an electric heater and worrying about whether the electricity comes from coal or nuclear.

 

[DrStupid]

It's more like taking note of the heat in the room from an electric heater and worrying about whether the electricity comes from coal or nuclear.

It's more like worrying about whether the electricity comes from a distant power plant or from batteries inside the room. My question in #8 still remains: Is Sun's core significantly involved in the generation of the mangetic field that heats the corona or not? Speculations about a suddenly stopping fusion don't answer this question.

 

[Drakkith]

Is Sun's core significantly involved in the generation of the mangetic field that heats the corona or not?

As I've said already, I don't think so. However I'm certainly not an expert in this area, so I'd be interested in hearing from someone who is.

 

[davenn]

Just seems myopic, ignoring the elephant in the room, a 15 million C solar core, that no one has as yet discovered a venting solution for heat dissipation.

You are not understanding or listening to what is being said.
Using your reasoning, the photosphere should be the same temp ( or somewhere close to) as the core
It isn't, it's millions of deg cooler at ~ 5600-6000 K (C).
But directly above the photosphere, the corona, is suddenly a million K ... so obviously the core wasn't doing it!
as the layer in between ( the photosphere) is VERY cool in comparison.
THAT was the reason why for many years it wasn't understood and a mystery as to why / how the corona could be so much hotter.

Divorcing the Corona from the photosphere and the core makes a mockery of the Coronal heating problem...

NO-ONE is divorcing the corona from the photosphere, please don't make statements that go against what is being told to you.
As I said in my very first post those 2 are closely interlinked because of the magnetic fields. I said to you in my first post that the
core wasn't directly linked in the energy transfer action and that comment still stands.

Wikipedia is a major referencing tool for millions of people. Disengaging the Core altogether from the Coronal Heating Problem is disturbingly disappointing to say the least.

and in general it is a good reference, but it can have issues, that is why it's VERY WISE to look through the lists of scientific references
at the bottom of any wiki page

It's only a disappointment to you because you refuse to listen and learn

But if nobody else is bothered, I'll let the subject drop.

well we are bothered and we are trying to help you, but you seem not to want to listen and learn.
There's nothing I or the other good people here can do about that, it's your loss Dave

 

[DrStupid]

As I've said already, I don't think so. However I'm certainly not an expert in this area, so I'd be interested in hearing from someone who is.

I'm not en expert either and I didn't find any useful information about the generation of Sun's magnetic field. That's why I asked the question. Maybe the answer is unknown. That could at least justifiy excluding the core from the discussion because it would be speculative.

 

[alantheastronomer]

I'm not an expert either and I didn't find any useful information about the generation of Sun's magnetic field. That's why I asked the question. Maybe the answer is unknown. That could at least justify excluding the core from the discussion because it would be speculative.

Globally, the Sun's magnetic field is generated by the dynamo action of the convective layer, so the core isn't directly involved, though it's energy generation is obviously the cause of the convection. Specifically, the knotting of the magnetic fields on the surface that cause sunspots and flares, are due to differential rotation. If you want to delve into the complexity of the processes, peruse the published papers of E.N. Parker.

Just seems myopic, ignoring the elephant in the room, a 15 million C solar core, that no one has as yet discovered a venting solution for heat dissipation.
Divorcing the Corona from the Photosphere and the core makes a mockery of the Coronal heating problem - the 2nd law of Thermodynamics - hot, through cold, to hot; it's a cop-out to what should be an intriguing and challenging problem.
Wikipedia is a major referencing tool for millions of people. Disengaging the Core altogether from the Coronal Heating Problem is disturbingly disappointing to say the least.
But if nobody else is bothered, I'll let the subject drop.

While the processes in the solar interior are integral to everything that occurs in the sun's subsequent evolution, the major puzzle is that the corona is hotter than the photosphere. Unless they found a link, either observational or theoretical, between the core and the corona, Wikipedia probably felt it unnecessary to include any mention of the core, not that they're ignoring it's importance but that it's inclusion wouldn't add any further insight into the problem's solution.

 

[eachus]

There is one way the core can transfer heat directly to the corona, via neutrinos. That certainly occurs but is a trivial component of the heating. A more interesting question is whether neutrinos collide with atoms in the upper layers of the sun, and produce muons. These can directly heat the corona, but more interesting is that a sufficient muon flux would create heat by muon-catalyzed fusion. Again has to occur, but the two processes may add a couple of degrees to the corona. (It would take me a month or three to simulate, but it isn't worth the effort.)

 

[Vanadium 50]

A more interesting question is whether neutrinos collide with atoms in the upper layers of the sun, and produce muons.

They don't.