Talk:Helioseismology/Archive 1

Archive 1

Question

What I am trying to find is an explication of the difference between local and global helioseismology. If I understand a bit, then local is the vibration around sunspots.There is scientific stuff and info enough about the subjects, but I cannot find clear definitions so that this amateur can go happily further on his way on and on. So, not too learned to start with. Who helps to bring clearness in my amateur mind? I followed some years, 1999-2003, the SOHO data as given on the web. Then was captured by the Cassini-Huygens thing and was absent in the SOHO lessons. Edybevk 11:36, 26 January 2007 (UTC)

In this URL [1] there is a discussion of helioseismology with lots of references, at least some at a less advanced level. In particular, there it says:

"The science studying wave oscillations in the Sun is called helioseismology." and "The three different kinds of waves that helioseismologists measure or look for are: acoustic, gravity, and surface gravity waves.". So maybe the definition in the article, which only refers to pressure waves, which are only one of the different kinds, should be amended. I know this is maybe a moot point if they aren't able to measure gravity waves (g), but maybe they can at the surface (f)?Puzl bustr (talk) 22:35, 7 November 2009 (UTC)

Here's some info about the local-global divide at [2]:

"Methods of helioseismology can be divided into two classes: global and local. The more traditional technique of global helioseismology consists of measuring the frequencies of the modes of oscillation and searching for a seismic solar model whose oscillation frequencies match the observed ones. This reveals the Sun’s large-scale structure and rotation as a function of depth and latitude. To complement global helioseismology, new methods of local helioseismology are being developed to make three dimensional images of the solar interior. The basic idea is to retrieve information at depth from the time it takes for solar waves to travel between any two surface locations." Puzl bustr (talk) 22:45, 7 November 2009 (UTC)

I'm working on standard solar model at present but may add some version of the foregoing ideas when I can. Puzl bustr (talk) 22:50, 7 November 2009 (UTC)

age of the sun bit cleaned it up. seemed a bit confused before. Ezkerraldean 13:19, 27 January 2007 (UTC)

added an explanation of how helioseismology can be used to infer the age of the sun Puzl bustr (talk) 12:11, 4 October 2009 (UTC)

Added meteoritic Sun age ref

Added meteoritic Sun age ref and moved the footnote for the seismic age ref to the right place. c.f Standard solar model. Puzl bustr (talk) 22:16, 7 November 2009 (UTC)

Added wikilinks to the appropriate sections.

BTW, the first sections could do with some footnote references for all the claims made there. Puzl bustr (talk) 22:24, 7 November 2009 (UTC)

Replaced broken external link

Replaced the broken link to a non-technical intro to Helio- and Astroseismology. Puzl bustr (talk) 16:21, 12 November 2009 (UTC)

Added refs

Using the Gizon and Birch external link added some references in the introduction of the article, to the idea that turbulence in the convection zone causes the acoustic waves and to the mention of far-side imaging, including sunspots, which I expanded to also include spaceweather forecasting, which now needs a ref. Puzl bustr (talk) 13:07, 13 November 2009 (UTC)

mention of far-side imaging really needs an explanation. Hope to chase this up. Puzl bustr (talk) 12:23, 15 November 2009 (UTC)

Added an explanation of far-side imaging.Puzl bustr (talk) 14:54, 15 November 2009 (UTC)

Analysis section

Added a discussion of oscillation data in its own section, mentioning Fourier analysis, taken from the Dalsgaard lecture notes. I mentioned frequency splitting as this concept is much used in the recent research literature: will add more if and when I can decipher some of this research. Did not mention inversion which is also important. Puzl bustr (talk) 13:58, 14 November 2009 (UTC)

Added a reference for the section, and removed the external link to the lecture notes to avoid duplication. Puzl bustr (talk) 14:21, 14 November 2009 (UTC)

Added refs for Sun's internal rotation and dynamo. Request diagram if possible, and f-mode reference.

Added refs in the Intro for Sun's internal rotation and dynamo. Also in Internal structure section added a copy of the ref for the internal rotation, taken from the Miess external link, which features a diagram [3]. If copyright restrictions allow, would be a useful addition to the Internal structure section. Anyone want to try this?

Copyright restrictions didn't allow it. But I added an image from the Commons which is suitable. Puzl bustr (talk) 19:27, 23 November 2009 (UTC)

The Dalsgaard notes state that observations of solar oscillations show f-modes of moderate and high degree, but without giving a reference. Some info should be added to the Types... section to indicate that f-modes have been observed, so that the subject is not merely about pressure waves. I've seen articles mentioning f-mode fequency splitting, but don't yet know of a precise reference.Puzl bustr (talk) 12:21, 15 November 2009 (UTC)

I found and added the reference for f-modes. Also, what about a diagram for the far-side imaging of the Sun, taken from [4], if possible? Puzl bustr (talk) 13:47, 15 November 2009 (UTC)

upgraded article assessment to c class and astronomy importance to Mid

With all the work done on the references, exposition and diagrams, from my POV the article deserves an upgrade in quality. I also upgraded the importance to Mid since e.g. Standard solar model has this importance and helioseismology has significantly improved the SSM in the last twenty years; plus in future is likely to improve understanding of (near-surface turbulent) solar convection, solar dynamo, sunspots and more. Puzl bustr (talk) 14:53, 15 November 2009 (UTC)

Added inversion section and more refs

Added a section describing helioseismic inversion in general terms, with the example of rotation and frquency splitting. Added refs for the detection of p-modes of low, medium and high degree (all from SOHO instruments). Added further explanation to the section on analysis of oscillation data. Not entirely sure if the reference to a grid of points is accurate, but it provided for a, to me, coherent overall explanation. Also added some more material about standing waves and normal modes with wikilinks to differentiate between local oscillations and global modes. In my POV the article now explains the topic. However, I've not yet added information about local and global helioseismology as at this stage it seems too technical for me to explain. Current external links explain it for readers more informed than me. Puzl bustr (talk) 17:09, 19 November 2009 (UTC)

Added local helioseismology section

Adapted it from the Birch living review. I hope it is not too technical but I fear it is! Still, in my POV it is helpful to give a summary of the aspects of the solar interior being studied by the technique, even if the techniques used themselves are perhaps too technical to be easily explained here. Puzl bustr (talk) 17:03, 22 November 2009 (UTC)

May do more work on this section to explain what I can. I also note that Living Reviews in Solar Physics has upcoming articles on many aspects of solar physics relating to helioseismology, in particular an upcoming review on global helioseismology, Thompson, M.J., 2005, “Global Seismology of the Sun and Stars”, Living Rev. Solar Phys., in preparation. So perhaps a section on global helioseismology will follow. And maybe separate articles on local and global helioseismology. Puzl bustr (talk) 10:34, 23 November 2009 (UTC)

Constructive interference?

The term "constructive interference" is used in the lead without a link. In optics, and more generally radiation, this ordinarily means in-phase interference, in which amplitudes add, as distinct from destructive interference as out-of-phase interference in which amplitudes subtract.

But this is only meaningful for reflections that occur within the space of considerably less than a wavelength. The reflections here seem to be far too gradual for anything coherent, and the resonances are therefore surely those associated with summation of intensities, where phase is irrelevant, rather than summation of amplitudes, and therefore where "constructive interference" is a meaningless concept.

Does "constructive interference" have a meaning in astrophysics that is different from its ordinary meaning in optics? --Vaughan Pratt (talk) 04:25, 14 October 2010 (UTC)

Hi

How do i get it to read out loud IAMBMO7 (talk) 19:30, 16 February 2018 (UTC)

Overhaul

I've been working on a fairly substantial overhaul of this page for some time and I've finally been bold and moved it from my user space into the main page. The final push was the realisation that I just won't have the time to make the further additions I once dreamed of.  :( I made an effort to keep existing text but it had become quite disjointed. I've also revised many of the figures. Happy to discuss my changes (or go ahead and edit them!) in what little free time I have at the moment. Warrickball (talk) 10:45, 13 March 2018 (UTC)

How is the data collected - Is it all Doppler shifts of emission lines

Needs another section before Data analysis that describes what data is collected, and using what instruments and techniques. If it's Doppler - of what spectral features ? What instruments record it ? What resolving power on the suns surface ? - Rod57 (talk) 13:00, 30 September 2018 (UTC)

Why “sound” waves

Hi. Why is the term “sound” waves continuously used in this article? Sound waves are just pressure waves oscillating within a range of hearing. It doesn’t make sense to call these sound waves, they’re just pressure waves. Can someone clarify? — Preceding unsigned comment added by 2601:249:601:97F1:2942:8424:9757:1BD (talk) 04:42, 6 January 2020 (UTC)

Sound wave would be the correct term. All media, regardless of whether our ears would work there, have a sound speed. The subsection on waves in the sound article even opens with "[s]ound is transmitted through gases, plasma, and liquids as longitudinal waves, also called compression waves." CoronalMassAffection (talk) 20:26, 27 August 2021 (UTC)