# What exactly is a quadripole magnet

**URL:** <https://boards.straightdope.com/t/what-exactly-is-a-quadripole-magnet/431003>\
**Category:** Factual Questions\
**Created:** [December 23, 2007, 7:11am UTC](https://boards.straightdope.com/t/what-exactly-is-a-quadripole-magnet/431003 "2007-12-23T07:11:57Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Saint\_Cad](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/saint_cad/32/18907_2.png) [@Saint\_Cad](https://boards.straightdope.com/u/Saint_Cad)\
**Post date:** [December 23, 2007, 7:11am UTC](https://boards.straightdope.com/t/what-exactly-is-a-quadripole-magnet/431003/1 "2007-12-23T07:11:57Z")

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Like Jupiter’s magnetic field? I know it has 4 poles, but is it 2 north and 2 south? Are they orthogonal? Are they 4 seperate poles: 1 north, 1 south, 1 “east” and 1 “west”? How would a regular dipole magnet react in such a field?

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**Author:** ![Sage\_Rat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sage_rat/32/399_2.png) [@Sage\_Rat](https://boards.straightdope.com/u/Sage_Rat)\
**Post date:** [December 23, 2007, 7:37am UTC](https://boards.straightdope.com/t/what-exactly-is-a-quadripole-magnet/431003/2 "2007-12-23T07:37:28Z")

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> **[Quadrupole](https://en.wikipedia.org/wiki/Quadrapole)**
>
> A quadrupole or quadrapole is one of a sequence of configurations of things like electric charge or current, or gravitational mass that can exist in ideal form, but it is usually just part of a multipole expansion of a more complex structure reflecting various orders of complexity.
> The quadrupole moment tensor Q is a rank-two tensor—3×3 matrix. There are several definitions, but it is normally stated in the traceless form (i.e. 
>   
>     
>       
>         
> Q
>           
> x
> ...

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**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\
**Post date:** [December 23, 2007, 5:28pm UTC](https://boards.straightdope.com/t/what-exactly-is-a-quadripole-magnet/431003/3 "2007-12-23T17:28:34Z")

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A couple of things: Jupiter [does have a dipole magnetic field](http://www.es.ucl.ac.uk/research/planetary/undergraduate/dom/magrev/gasmag.htm). I also has a quadrupole component, so a dipole field alone doesn’t fully describe its magnetic field.

Also, in **Sage Rat** ’s link, in the magnetic quadrupole field picture, the quadrupole field is the region in the middle of the magnets. Away from the magnets, the field is actually octopole, with zero dipole and quadrupole moments.