Talk:Thomson scattering

Redirect
Electron scattering redirects to this page, but this must be a mistake? In my opinion, "Electron scattering" refers to the scattering of electrons (for example by atoms), not scattering _by_ electrons. If no-one objects, I'll remove the redirect and just write a small stub article on "Electron scattering". O. Prytz 22:58, 30 December 2005 (UTC)


 * Done O. Prytz 10:52, 31 December 2005 (UTC)

Compton Scattering
I found it surprising that there's no mention of Compton scattering on this page, even though the only difference seems to be whether or not the electron absorbs energy from the incident photon. I can't really think where to fit it in though... Warrickball (talk) 14:03, 11 May 2008 (UTC)

Downplayed CGS units
The equation for the Thomson differential cross section was given as

\frac{d\sigma_t}{d\Omega} \equiv \left(\frac{q^2}{mc^2}\right)^2\frac{1+\cos^2\chi}{2} = \left(\frac{q^2}{4\pi\epsilon_0mc^2}\right)^2\frac{1+\cos^2\chi}{2} $$

The use of SI and CGS units in the same equation is extremely confusing. It's like placing an egg in your handbag -- it's okay for a few minutes if you're careful, but if you leave it for long you're likely to forget the setup and make a mistake.

To remedy this, I removed the CGS units (leaving just a mention in the text).

Is this right? Or is there a "segue" from CGS to SI that occurs at this point in the text -- that I missed through inexperience-- and that I have now obscured?

84.226.185.221 (talk) 13:08, 12 October 2015 (UTC)

Something is wrong with the Thomson differential cross section
I don't understand how:

(1) At first, we treat σt as a constant to be carried along while integrating over the sphere. It gets multiplied by a factor of 1+cos2χ coming from the emissivity coefficients εr and εt.

(2) But then, we obtain σt itself by integrating a non-constant density dσt/dΩ over the sphere. The non-constant density contains an internal factor of 1+cos2χ.

Is the factor of 1+cos2χ supposed to be incorporated in σt, or not?

What is the exact relation between the Thomson differential cross section dσt/dΩ and the emissivity coefficients εr and εt?

It seems as if this derivation was constructed from two partial, slightly disparate versions, perhaps from two different sources, but laid on top of each other and not fully integrated.

84.226.185.221 (talk) 13:08, 12 October 2015 (UTC)

Classical radius
The article says that a quantity called classical radius of a charged particle is convenient to be defined. Can also proton have a classical radius defined for for it?--5.2.200.163 (talk) 13:42, 12 February 2016 (UTC)

High Energy Lasers
This article should be expanded on, by someone more invested than I, with respect to this article: https://www.sciencedaily.com/releases/2017/06/170626124428.htm and this abstract: https://www.nature.com/nphoton/journal/vaop/ncurrent/full/nphoton.2017.100.html

which says

Electron–photon scattering, or Thomson scattering, is one of the most fundamental mechanisms in electrodynamics, underlying laboratory and astrophysical sources of high-energy X-rays. After a century of studies, it is only recently that sufficiently high electromagnetic field strengths have been available to experimentally study the nonlinear regime of Thomson scattering in the laboratory. Making use of a high-power laser and a laser-driven electron accelerator, we made the first measurements of high-order multiphoton scattering, in which more than 500 near-infrared laser photons were scattered by a single electron into a single X-ray photon. Both the electron motion and the scattered photons were found to depend nonlinearly on field strength. The observed angular distribution of scattered X-rays permits independent measurement of absolute intensity, in situ, during interactions of ultra-intense laser light with free electrons. Furthermore, the experiment's potential to generate attosecond-duration hard X-ray pulses can enable the study of ultrafast nuclear dynamics.

ty gl hf — Preceding unsigned comment added by 72.196.144.9 (talk) 03:23, 30 June 2017 (UTC)