I Magnetar Mystery: How Do Neutrons Generate a Magnetic Field?

[swampwiz]

If a magnetar is a neutron star, how do the neutrons composing the star generate a magnetic field? A neutron has zero charge, so it generates no magnetic field.

 

[Hornbein]

If a magnetar is a neutron star, how do the neutrons composing the star generate a magnetic field? A neutron has zero charge, so it generates no magnetic field.

Neutron star cores contain a percentage of electrons and protons. I've seen estimates as high as ten percent.

However the magnetic field is inherited from the star that went supernova. Magnetic fields are remarkably persistent. The neutron star is far smaller than the original star so the magnetic field becomes very concentrated.

In the case of a magnetar, there was a short-lived geodynamo in the early days of the neutron star. Once the core is cool enough to be superconductive, there are no more convection currents and hence no more geodynamo. I haven't looked at these things for 15 years so I might not remember it correctly, that's the best I can do.

 

[Drakkith]

If a magnetar is a neutron star, how do the neutrons composing the star generate a magnetic field? A neutron has zero charge, so it generates no magnetic field.

That's not true. Neutrons have an intrinsic magnetic moment, though I'm unsure if this contributes to a magnetar's magnetic field or not. See here: https://en.wikipedia.org/wiki/Neutron_magnetic_moment

 

[Vanadium 50]

A neutron has zero charge, so it generates no magnetic field.

Not true. A neutron has a magnetic moment - i.e. is a little magnet in and of itself.