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chentadot
2016-Sep-03, 07:45 PM
How come a rotating neutron star has a magnetic field?
Aren't neutrons supposed to be nutral?
What charge causes this field?
Thanx, Chenta.

antoniseb
2016-Sep-03, 08:02 PM
How come a rotating neutron star has a magnetic field?
Aren't neutrons supposed to be nutral?...
Neutron stars are more complicated than a pure sphere of only neutrons.
The causes of the fields are fairly complicated, and can't be summed up in a few sentences.
Hopefully one of the other members will take a stab at giving an answer.

Ken G
2016-Sep-03, 08:41 PM
You're right, the surface layers of neutron stars have lots of charged particles. What's more, there is a tendency for magnetic fields to be "frozen in" to plasmas like that, so when the star contracts, the magnetic field gets concentrated. That's why the fields are so strong when a pulsar first forms.

Cougar
2016-Sep-04, 12:23 AM
How come a rotating neutron star has a magnetic field?
Aren't neutrons supposed to be nutral?
What charge causes this field?


All stars have a magnetic field, as does Earth. The inner structure of the neutron star and its high rotation speed create a dynamo effect. This is similar to how Earth's field is created, which is a lot weaker, of course. [Edit: Looks like I better add a source. (http://abyss.uoregon.edu/~js/ast122/lectures/lec19.html) :) ]

trinitree88
2016-Sep-04, 01:27 AM
The magnetic field is stronger @ the poles of the star. If the field is greater than about 10 exp. 12 Gauss...the halflife of the neutrons there is greatly affected..see https://www.google.com/url?sa=t&source=web&rct=j&url=http://link.aps.org/doi/10.1103/PhysRev.187.2141&ved=0ahUKEwi58arlxfTOAhXG7yYKHY2fBdYQFggqMAQ&usg=AFQjCNFv3mK1H_R83PEv5LDnavVIO0U21
And...that happens to be in play for some neutron stars....pete

fagricipni
2016-Sep-04, 07:06 AM
Don't the neutrons themselves also have a magnetic dipole moment? I don't know, though, if that has a significant effect regarding the magnetic field of neutron stars; they might be so disaligned that that is not a significant effect in contrast to the other sources of neutron stars' magnetism.

trinitree88
2016-Sep-04, 05:36 PM
fagricipni. 1. Yep they do have a moment. 2. ~ 8 Years ago attended a lecture @ Theoretical Physics colloquia @ MIT, and the discussion was on packing factors for nucleons in degenerate matter. Turns out, @ the time, models where the nucleons assumed a bean shape rather than spherical symmetry made the most sense, and that would inherently transition to axial rather than radial symmetry. I'll look for the original paper. pete

SEE: https://forum.cosmoquest.org/archive/index.php/t-80628.html

publiusr
2016-Sep-10, 06:23 PM
Speaking about thin beams
http://www.space.com/33699-neutron-stars-unite-to-form-pencil-thin-radiation-beams-video.html

grapes
2016-Sep-11, 01:02 AM
Don't the neutrons themselves also have a magnetic dipole moment? I don't know, though, if that has a significant effect regarding the magnetic field of neutron stars; they might be so disaligned that that is not a significant effect in contrast to the other sources of neutron stars' magnetism.
Yes, neutrons have magnetic moment, it's almost as large as that of protons--but a few magnitudes less than electrons. Most "everyday" magnetism is from electron moments, rather than loops of current.