Does the cause of the solar magnetic dynamo cause mixing in solar interior

newtonian · Sep 22, 2004

The solar corona was recently discovered to be heated by magnetic fields which float to the solar surface from the interior which is caused by an interior magnetic dynamo. Do these floating magnetic fields constitute evidence of motion of ions deep inside the sun? And therefore, is the standard model of stellar evolution wrong in the case of our sun - as it assumes zero mixing of hydrogen depleted solar core gas and outer hydrogen rich zones of gas? And just how different are stars in their radiation - for example, how variable are stellar coronas in our galaxy and universe? How variable are stellar magnetic fields, and their causes?

newtonian · Sep 24, 2004

Saiph - You posted on my other recent thread: Saiph asteroid 09/22/04 10:24 PM Oh, and mixing is a very important aspect of stellar life-cycles. That was concerning a brown dwarf collision, but it applies equally to mixing caused by ions in motion in our sun's interior which would be one model to explain those floating solar magnetic fields from the interior (how deep their origin?). You all - it is generally believed that magnetic fields in astronomy are caused by differential rotation in core areas. The reason Venus is thought to have very little of a magnetic field is its slow rotation. The reason Mars is thought to have very little of a magnetic field is that the core does not allow differential rotation. Correct?

Saiph · Sep 24, 2004

magnetohydrodynamics (which is the name of the field required to answer this) is unprepared to answer this. We don't have the computing problem. There's a reason why anything odd in astronomy is usually explained (speculatively of course) with "a shock" or "magnetic fields". I usually accompany such statements with some sort of dramatic theme music, in my head anyway. It's a shock! Da da doooonnnn From what I've gathered, what work we can do suggests it isn't an issue near the core (everything is randomly distributed and averaged out, not to mention smaller portion of moving ions). <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

newtonian · Sep 25, 2004

Saiph- ah - formerly ricimer? And I am formerly paulharth6 (as per my real name). Alas, in the crashed SDC there were some good links to varying models for the magnetic dynamo heating the corona - I don't know if I backed that info. up somewhere in my files, of which I have too many! From my brain (interesting filing system) I remember that the models varied on where the dynamo originates or is located. It will be easier for me to find a clue in our literature - stay tuned!

newtonian · Sep 25, 2004

Saiph - This is an interesting article - I wonder if AURA has a website that we could check out for more current information on the sun's interior rotational motions, etc.? Anyway, here is an excerpt from a 1990 article about the Sacramento Peak Observatory at Sunspot, near Cloudcroft, New Mexico: "Later, in 1957, a nonprofit organization, AURA (Association of Universities for Research in Astronomy, Inc.), was organized in connection with the Kitt Peak National Observatory in Tucson, Arizona; the Cerro Tololo Inter-American Observatory in La Serena, Chile; and the Space Telescope Science Institute in Baltimore, Maryland. AURA felt that by sharing scientists and information, all could gain more understanding of the sun. We were beginning to see that this isolated observatory had connections in various parts of the earth. The Quivering Sun Dr. Bernard Durney, a research director, graciously offered to answer some questions about the sun. He explained that he is working in the field of solar seismology. We needed an explanation of what that meant. It seems that it was first studied there at Sacramento Peak. He explained: "The sun not only rotates on its axis but moves in many other ways that can be studied by viewing its surface constantly and seeing changes that occur. From these changes, we can formulate ideas about what may be occurring inside the sun and then plan studies to confirm or disprove our ideas." "About 1970," he continued, "a quivering, or shaking, of the sun was predicted. It is much like the shaking, or vibration, that occurs when a large bell is rung. One can also think of the illustration of a pebble thrown into a pond and how it causes the entire surface of the pond to be affected as the rings of waves cross the pond from the point of impact. The difference is that the waves in the sun go throughout the sun in all directions." It appeared that these vibrations originated at different level

Saiph · Sep 26, 2004

Don't worry paul, I can recognize you pretty easily. Who else ressurects posts about reviving the sun? Tends to triple post? And quotes Isiah 40:22 and Job 38: something or other, to back up and/or start discussions. Just teasing, you've gotten a lot better about the quoting and multi-posting. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

newtonian · Sep 27, 2004

Saiph- Thanks - glad to know you knew it was me. And, whenever I see an apparent contradiction I always research to see if the contradiction is real, and, if so, which is more likely to be correct. Sometimes we really can't know yet - with our limitied observations. However, other times it is not that we cannot know, but rather that it has not been researched or explored enough to find the answer to that specific question. Now that I re-examine the evidence in that article, It seems to me that even if the primary magnetic dynamos are not as deep as the core of the sun, wouldn't the magnetic field lines nevertheless penetrate the core and cause mixing - which, of course, would cause more secondary magnetic fields! And that, in turn, is not considered in the standard model of stellar evolution as a factor to determine the life-span of our sun. Related to this question is whether our sun is relatively unique in respect to its magnetic properties and the causes thereof - including the specific values of internal rotation differences. I.e., to what extent does "star differ from star in glory" or radiation, including electromagnetic in coronas and internally.?

Saiph · Sep 27, 2004

when you get so much stuff together to make an object (in this case the sun) uniqueness is hard to come by. As for magnetic fields in the core, sure, there probably are some present. The question is: Is that significant? <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

newtonian · Oct 1, 2004

Saiph - Yes, I agree. And I would extend your question mathematically - how significant is significant. What I mean is this. The mixing time. For example, on earth the mixing time of the connected oceans (Atlantic, Pacific, etc.) is about 1,000 years. That is a fairly slow mixing time - compared to the effects of global warming by man. [which is relevant since the oceans are both a carbon dioxide sink and also absorb and give off heat] However, if our sun has a much slower mixing time from core to other layers 'above' it, say one million times slower, it would have a mixing time of one billion years. Actually I suspect an even slower mixing time, on the order of 10 billion years. Compare evolution theory - what we cannot even perceive experimentally is supposed, by some scientists, to have produced all life forms on earth in well under 10 billion years. The point is that if the sun has a mixing time somewhere near in powers of 10 to 10 billion years, then this will drastically alter its predicted life span. Even a much slower mixing time will still change the predicted life span significantly.

newtonian · Oct 2, 2004

Saiph - Note the extreme magnetic differences that cause Magnetars. OK, that is in a fairly recent Scientific American article - I will look it up later. The point is that star differs from star in glory (aka radiation), and this fact is not factored in when stellar life spans are calculated. If I remember correctly, magnetars differ in internal magnetism quite a bit from average.

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