Talk:Quadrupole magnet

Description of the field in the z axis?

There's a description of the B field in the plane 'perpendicular to the beam' at the bottom, can someone add the field in the axis parallel to the beam? 86.130.159.75 (talk) 04:14, 9 March 2015 (UTC)

F vs D quadrupole orientation

The description of them and their difference doesn't make a lot of sense as written unless one already understands the material...I don't think just a link to Maxwell suffices here. Let's say there are N poles positioned at 0° and 180° and S poles at 90° and 270° (relative to an observer looking along the direction of the beam). What directions are focusing, and what directions are defocusing (for some given sign of the particle charge)? The confusion is that it feels like a C<cub>4 axis--every 90° one is at the same position relative to "an opposing pair of poles". DMacks 02:41, 3 March 2006 (UTC)

Shouldn't the arrows on the animation at the bottom swap around with the poles?Grj23 (talk) 16:11, 31 March 2008 (UTC)

Oh yeah, good point. Don't know off-hand how to fix it though. I don't have an animated GIF editor.- (User) WolfKeeper (Talk) 16:24, 31 March 2008 (UTC)

In terms of the description of the focusing and defocusing, wouldn't it be helpful to refer to the F=ev x B type formula (or whatever it is). I think that would be clearer (assuming I've understood what's going on!). I think this was quite helpful though Grj23 (talk) 16:11, 31 March 2008 (UTC)

The equation seems somewhat confusing. It should really define what letter stands for as in electromagnetism (which these types of magnets contribute to) E can stand for Energy and Electric field. F=qvB is the way I understand it so I am unsure E stands for energy or electric field. Some explanation of the equation would be beneficial.--Ajihood (talk) 05:57, 25 August 2008 (UTC)

E has to be a field here - the bold typeface indicates a vector quantity. It is always a good idea to see if the dimensionality makes sense. Eg speed [length / time] * time [time] = distance [length] is right whereas speed[length / time] * time [time] = volume [length * length] is clearly silly. I usually do it with units themselves (SI units are decent ones to use). In this case Force [N] = charge [C] * Field strength [N/C]. (Newtons per Coulomb is the same as Volts per meter.)Cambion (talk) 14:03, 26 August 2008 (UTC)