Talk:Ponderomotive force

Factor 1/4 ok?
Looking at [one of the original papers], I find essentially the same equation with a factor 1/2, not 1/4 as in the first paragraph of the Wikipedia article. What is correct? -Anastasius zwerg (talk) 15:56, 27 October 2008 (UTC)
 * Sorry, not really problem; I got it in the meanwhile: it is 1/2 with the time averate for $$E^2$$, but 1/4 with the amplitude $$E_0$$ for a field varying like $$E_0 \cos \omega t$$. --Anastasius zwerg (talk) 16:17, 27 October 2008 (UTC)

Ponderomotive force can affect a neutral particle
Although the article defines ponderomotive force as involving a "charged particle" perhaps the definition might be clarified in considering that "weak forces on neutral atoms in inhomogeneous light fields may arise from the dynamical polarization of an atom" and can produce "previously unconsidered extremely strong kinematic forces on neutral atoms in short-pulse laser fields."

By the way, Eichmann et al. touch on Paul traps and the Kapitza–Dirac effect, which ought also to be mentioned in the Wikipedia article on ponderomotive force. This is way beyond my ken, but perhaps someone could manage all this. Myron (talk) 00:29, 30 October 2009 (UTC)

frequency
hello, the fact that ponderomotive force increases while the frequency decreases suggests that it is not valid on low frequency. otherwise it would become infinite with a... static force. Am I wrong?Klinfran (talk) 21:04, 2 August 2010 (UTC)

As the frequency decreases the wavelength of the radiation will increase. Also the gradient of the electric field will decrease: the electric field changes more slowly over the length scale of the charged particle. Hence the force should not diverge to infinity... I hope. —Preceding unsigned comment added by 163.1.241.234 (talk) 12:56, 28 March 2011 (UTC)

history
The page is badly missing something on the history of the term ponderomotive force. Originally it meant a force that acts upon matter with weight. So gravity was considered a ponderomotive force, for example — Preceding unsigned comment added by 82.24.86.223 (talk) 22:31, 3 September 2011 (UTC)

Loose/confusing terminology/jargon in derivation section?
It seems that some inconsistent terms are used in the derivation section (version accessed 22 July 2013). The "equation of motion" becomes "the force equation"; x is both a variable indicating position and a "motion" that can "oscillate". At graduate level we grow accustomed to this kind of thing, but should this be written in more accessible form? Pvkwiki (talk) 12:13, 22 July 2013 (UTC)

Also it feels like some steps are missing there. — Preceding unsigned comment added by 68.5.67.232 (talk) 20:02, 29 September 2020 (UTC)

Derivation only works when the oscillations and gradient both point in the same direction.
The given equation for Ponderomotive force does not take the direction of the electric field into account. $$\mathbf{F}_{\text{p}}=$$$-\frac{e^2}{4 m \omega^2}$$\nabla$$(E^2)$ However, the derivation relies on the oscillations being in the same direction as the gradient. --68.5.67.232 (talk) 20:15, 29 September 2020 (UTC)

Etymology
I just added an etymology section. It is because I am learning what ponderomotive is and I had no idea what the term meant, so I added the section. TheRealBalalaikaMaster (talk) 22:03, 27 September 2023 (UTC)