Talk:Synchrotron radiation

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I am surprised you call linear acceleration synchrotron radiation; I would likely have picked "bremsstrahlung." The polarization (for a swarm of electrons with a power law spectrum) is polarized, but not perhaps "highly polarized" as was derived by Legg, M. P. C., & Westfold, K. C. 1968, ApJ, 154, 499.Pdn 16:36, 14 Jun 2005 (UTC)

"* Brilliance of about 10¹⁴."? 10¹⁴ in what units?

I need to comment here on the last part of the page. it is said:

Plasma physicist Hannes Alfvén suggested that ions travelling along a Birkeland current into a double layer, may be accelerated to relativistic velocities, which in an inhomengous magnetic field or pinches, accelerate ions to relativistic velocities through magnetic fields, producing synchrotron radiation.

However, there is absolutly no need for inhomogeneous magnetic fields. Charged particles will have, in general, a component of their velocity perpendicular to the local magnetic field, will thus gyrate and emit synchrotron emission. The whole end of this sentence does not make sense. Tusenfem

Removed for now. Be bold. Nonsuch 05:52, 1 March 2006 (UTC)

I've restored the deleted paragraph. There were TWO citations in the paragraph. Your job as editor is to clarify, not to remove stuff you don't understand. To find out what Alfvén meant, read the papers (the second paper is online in full (PDF)), asks other editors for clarification, and then rewrite it in words that you understand yourself. --Iantresman 10:15, 1 March 2006 (UTC)

I've removed POV-pusher Iantresman's attempt to circumvent consensus. Alfven's contribution is not worthy of contribution in this summary article. Just because you have a citation doesn't meant that it is editorally a wise idea to include the prose. --ScienceApologist 15:07, 1 March 2006 (UTC)

You really must get a handle on the meaning of Point of View. (1) I did not present MY point of view. (2) I did not present anyone else's point of view in a non-neutral manner. Unless you can find any SPECIFIC example in this example of where I contravened neutral point of view, I would be delighted to know.

That YOU'VE decided what is "worthy of contribution" IS a point of view. So tell me oh great one, what constitutes your worthiness? The fact that Alfvén was the first person to predict synchrotron radiation in space, based on his Nobel Prizing winning developement of magnetohydrodynamics isn't good enough for you? --Iantresman 16:10, 1 March 2006 (UTC)

There are two issues here. The first is that the sentence in question doesn't seem to make any sense. It's not even grammatically correct. It's a side issue to the subject of the article, so lets improve the article by removing this confusing paragraph. The other issue is the gratuitous portrait. In general, we don't stick a picture of everyone involved with a subject at the top of the subject article. Also, are you sure that the picture of Alfvén is fair use? The tag seems to indicate otherwise. Nonsuch 15:22, 1 March 2006 (UTC)

If the sentence doesn't make sense, we can improve it. Have a look at the citations, and propose an alternative wording. If you'd rather not, perhaps ScienceApologist can provide a dummed-down explanation of Alfvén's explanation. Do you think I should look through some of the other astronomy articles, and remove all the sentences that don't seem to make sense to me.

As for the image of Alfvén, I believe that ANY relevnant image in an article, especially in such a dry subject as this, is better than no image. Alfvén is not just vaguely related to the subject, but as mentioned earlier was the first person to predict synchrotron radiation in space. As for fair use, I don't know. --Iantresman 16:10, 1 March 2006 (UTC)

The postage stamp image shouldn't be in any of the articles it is (stamps are only fair use when illustrating the stamp itself), but Image:Hannes-alfven.jpg is okay. — Laura Scudder ☎ 17:16, 1 March 2006 (UTC)

The two mentions of "GeV-frequencies" should be "GHz-frequencies" surely? [The mention to "GeV-range" energies appears correct.] 203.109.242.80 07:11, 9 May 2006 (UTC)

I've restored the paragraph deleted by ScienceApologist on the grounds that (a) it provides a historical background to Alfvén's correct prediction of synchrotron radiation (b) it is factually accurate (c) supported by two citations.

That other summaries omit the information is irrelevent; this is not most other summaries. --Iantresman 00:01, 22 May 2006 (UTC)

[edit] Prediction of synchrotron radiation and reason

As noted by the article, synchrotron radiation was first predicted by Hannes Alfvén and Nicolai Herlofson in 1950, and subsequently confirmed by Geoffrey R. Burbidge. The reason behind such a prediction, (indeed any notable prediction), would seem to be not only non-trivial, but consistent with the scientific method. Alfvén's reasoning then, is not just another theory, but the one which enabled him and Herlofson to successfully predict synchrotron radiation.

If "... there are a billion theories on the innumerable production methods of sync rad. in space .." why is one unverified theory left in the text? --Iantresman 11:26, 28 May 2006 (UTC)

That's not what I removed. I have no doubt he was the first to predict them existing. Its his theories in the 80's on ions in Birkeland currents and double layers that are not worth including and what I removed. Is it possible that's what's happening somewhere in the universe? yes, but its certainly not a major part of sync. radiation theory. its just a grasping attempt to validate the fringe "plasma universe" nonsense and doesn't belong here. The section which I removed in no way elucidates "Alfvén's reasoning ...which enabled him and Herlofson to successfully predict synchrotron radiation", it came decades after thier prediction which originally concerned electrons in a magnetic field, not ions in plasma currents. The first cited paper has exactly 2 (TWO!) citations since publication 20 years ago! The second has maybe a dozen and a half, the vast majority of which are plasma universe paper citations. Alfven was a fine scientist, not some all knowing god to be worshipped, stop this pov pushing. --Deglr6328 16:49, 28 May 2006 (UTC)--Deglr6328 16:49, 28 May 2006 (UTC)

[edit] Multiband image of M87's jet does not show only synchrotron radiation

And therefore it has been removed. --ScienceApologist 21:19, 28 May 2006 (UTC)

No-one said that the image of M87 shows only synchrotron radiation. But according to Geoffrey Burbidge, synchrotron radiation was first detected in M87. According to a Gemini Observatory Press Releases page, "Synchrotron Radiation, is the primary radiation that is emitted by galactic jets such as the prominent jet in M-87". The page has four images of M87 in different wavelengths. Why don't you choose the one that your feel best exemplifies M87 and the emission of synchrotron radiation. The caption I believe was both factually accurate, conforms to NPOV, and relates to M87 and synchrotron radiation. --Iantresman 22:04, 28 May 2006 (UTC)

Synchrotron radiation was indeed first detected in M87, but the four wavelength-band images are not all synchrotron radiation. The image is best left for discussion at galactic jets. Why not just include the standard image of Elliptical Galaxy M87? --ScienceApologist 23:07, 28 May 2006 (UTC)

[edit] sales brochure?

The section "Synchrotron radiation from storage rings" reads like a sales brochure, or a research prospectus written by someone who's enthusiastic about applications of synchrotron radiation. The article is about the physical phenomenon in general, however. One could equally well have written this section from the point of view of a particle physicist, for whom synchrotron radiation is a nuisance. There's nothing wrong with talking about applications, but it should be clear that that's what's being talked about, and it shouldn't be incongruously prominent in the article.--76.81.164.27 02:53, 10 March 2007 (UTC)