Magnetic fields due to neutron stars?

Question

If a magnetic field is present only due to moving charge, then why does a neutron star have a magnetic field of ~10^10 T?

Answer 1

Best Answer - Chosen by Asker

First and foremost, neutrons do have a magnetic moment associated with them. This is a prime indicator that the neutron has internal structure and served as a start for development of QCD (Quantum Chromodynamics) - quark theory. So even if the core was just composed of neutrons (unlikely now we believe), it would still have a magnetic field associated with it.

Another factor to consider is the original magnetic field of the parent star would not vanish but rather would be trapped by the condensing core and surface.

Which leads to the final issue, based upon data gleamed from x-ray analysis of flare events, current models have significant layered structure for a neutron star. Starting with a proposed crust of nuclei locked into a crystalline lattice with electrons flowing as BCS pairs through this matrix. A type II superconducting surface if you will.

So you see there are many different ways for neutron stars to have magnetic fields. Interesting research from a few years back was that when researchers were able to measure the field intensity by means other than interpolating field strength by rotational slowing, they ascertained a valve for one neutron star's magnetic field to be considerable less than expected. This indicates that we may be over estimating total field strength for some pulsars and neglecting additional means of reducing the spin.

The area of condensed matter physics is an exciting one we expect to continue to surprise us over the next decade or so.

Hope this helps.

Asker's Rating:

Asker's Comment:

It did help indeed. I guess I have to be doing more than first year physics regarding neutron stars to be able to understand better what's happening.

Thanks.

Answer 2

Probably due to the layer of liquid strange matter below the iron crust. If it exists like they say, it might have a different rotation period, which in addition to the density, is probably responsible for the extreme magnetic field.