3 ms·
The wiki on this topic is not to bad [0]. Essentially, it's a configuration of 2 south poles and 2 north poles. It's pretty important if you're doing quantitat
by pbmonster 3y ago
The wiki on this topic is not to bad [0].
Essentially, it's a configuration of 2 south poles and 2 north poles. It's pretty important if you're doing quantitative magnetism. Many magnetic configurations don't generate a pure dipole-like field, but also need higher order contributions - like quadrupole and octopole moment - if you want to model/calculate the field.
Quadrupoles also have useful technical properties, you can use one to re-focus the beam in a particle accelerator, for example. In a sense, they act like magnetic lenses.
[0] https://en.wikipedia.org/wiki/Quadrupole https://en.wikipedia.org/wiki/Quadrupole
- eszed 3y agoThanks. I looked at that, but I don't have the maths background to follow the real explanation. I get the four bar magnets or four coils stuck together, as an example of the charge state, but that looks simplified to the point that it's maybe not real. I think I'm trying to bridge a gap in my understanding between "this is a convenient way to refer to a complex interaction between multiple magnetic fields", and "this is a object (constructed? naturally occurring?) that I can hold in my hand". Or, maybe that's not even a reasonable mental model / distinction - magnetics be freaky.