Talk:Gyroradius

Cyclotron frequency redirects here, but there isn't even a formula for cyclotron frequency. 66.188.130.252 (talk) 11 December 2007 —Preceding comment was added at 05:07, 12 December 2007 (UTC)

In the numerical formula with units, radius = (3.3 m) pT / qB is wrong: it should be (0.3 m), so I changed it. See, for instance, Jackson's Electrodynamics.

--79.78.150.243 (talk) 16:30, 26 May 2008 (UTC) Jim Pivarski

Ambiguity

We have an article Radius of Gyration stating "Radius of gyration or gyradius refers to distribution of the components of an object around an axis..." as well as an article Gyroradius stating "The gyroradius (also known as radius of gyration, Larmor radius or cyclotron radius) is the radius of the circular motion of a charged particle in the presence of a uniform magnetic field..." In neither of these two, which treat completely unrelated phenomena, the other meaning of "radius of gyration" is mentioned. I think we would at least need a pointer "For the other physical effect named radius of gyration see...", if not a full disambiguation page for "Radius of gyration". — Preceding unsigned comment added by Seattle Jörg (talk • contribs) 13:37, 19 January 2017 (UTC)

I totally agree with you, please my "Ambiguity" titled text below. The electron performs both motions when inside a homogeneous external B field. A "Radius of gyration" of its magnetic moment around the B field vector described as Larmor precession at angular velocity ~28.2 GHz/T and second the "Gyroradius" described in this article here of a much smaller angular velocity and larger radius.

The source of the ambiguity here in this article is that the alternative term "Larmor Radius" is added to the text that causes confusion to the reader implying that both phenomena are the same. But "Larmor radius" is referring to the spiraling translational motion radius due to the Lorentz force and not to the quantum related "Larmor precession" radius of the electron at ~28.2 GHz/T (https://en.wikipedia.org/wiki/Larmor_precession) which is a fixed value at +/- 54.7° from the z-xis of the B field (see https://qsstudy.com/sample-question-electron-spin-and-orbital-angular-momentum/). The common "Larmor" term causes the whole confusion. This must be somehow clarified inside the Gyroradius article and disambiguate. In Larmor Precession the magnetic dipole moment vector of the electron and spin axis, wobbles around the z-axis of the B-field similar to the wobbling of a mechanical spinning top. The Gyroradius is the spiraling motion of the WHOLE electron particle and its magnetic moment around the z-axis B field vectors with a much slower angular velocity. 147.95.130.109 (talk) 12:07, 8 October 2022 (UTC)

Ambiguity

The frequency calculation for the electron in section https://en.wikipedia.org/wiki/Gyroradius#Variants is irrelevant to the article here and misleading since it refers wrongly to the spin Larmor precession phenomenon of the electron (i.e. wobbling of its spin magnetic moment around the B vector of a homogeneous z-axis external field), reported here, https://en.wikipedia.org/wiki/Gyromagnetic_ratio#For_an_isolated_electron and also here, https://en.wikipedia.org/wiki/Larmor_precession and not to any translational spiraling motion of radius the Gyroradius this article herein is referring to. Therefore, the term Larmor radius (i.e. Gyroradius) is not to be confused with the phenomenon of electron's Larmor Precession and its Gyromagnetic ratio and any radius associated with this type of spin non-translational rotation which is different from the Larmor radius which refers to the whole particle trajectory spiraling around the B vectors of the external field with spiral radius value the Larmor radius and not referring to the additional motion, wobbling of the electron's spin magnetic moment vector around the B vector of the external field. The electron will never spiral with ~28.2 GHz/T instead it spin magnetic moment vector wobbles at that frequency and also the associated wobbling radius in this case is fixed and invariant at +/- 54.7° from the z-axis B-field vectors forming the two Heisenberg Uncertainty cones, https://qsstudy.com/sample-question-electron-spin-and-orbital-angular-momentum/ . These are different concepts and phenomena and confusion comes from the fact that the same prefix term "Larmor" is used in both cases. For more information about "Larmor Radius" please consult this reference here: https://www.sciencedirect.com/topics/physics-and-astronomy/larmor-radius 147.95.130.109 (talk) 11:28, 13 September 2022 (UTC)

Here is a more canonical reference about this topic: https://encyclopediaofmath.org/wiki/Larmor_radius .

The Larmor radius is caused by the Lorentz force. 147.95.130.109 (talk) 11:50, 13 September 2022 (UTC)

In a nutshell, what I'm saying the the gyroradius is different from the Larmor precession of the free electron (wobbling) inside an external homogeneous magnetic field. The electron performs both type of motion simultaneously. One of larger radius and much slower the gyroradius described in this article here and the second much faster larmor precession wobbling at ~28.2 GHz/T of its intrinsic magnetic moment around the B field vectors at a much smaller radius. The end result is a wobbling and at the same time spiraling translational motion of its magnetic moment inside the external B field. 147.95.130.109 (talk) 11:32, 8 October 2022 (UTC)