If a star undergoes a supernova explosion, how does it retain its magnetic field to excite the moving particles to near speed of light velocities as stated in observations of NASA?


1 Answer 1


The magnetic field of neutron stars is generated by a magnetohydrodynamic dynamo. This is essentially the same process that forms the magnetic field of the Sun and the Earth, but continued to an extreme form due to the extreme nature of neutron stars.

Magnetic flux is conserved, so as the core of a massive star collapses, the flux is not lost, but becomes concentrated in the relatively tiny volume of the neutron star. This can start a magnetohydrodynamic dynamo, in which heat and rotational energy of the neutron star (both of which are intense) cause enormous flows of electrically conducting material in the star and consequently enormous eddies of electricity, generating a magnetic field. The field then acts to maintain the flow of electricity and the system is stable as long as it can be powered by the rotation and heat of the star.

So the key points. A collapsing star keeps its magnetic field and concentrates it. The magnetic field of a neutron star can generate a dynamo that further intensifies the field. Neutron stars are extreme objects with extreme properties.

  • $\begingroup$ Thank you for this answer , im not familiar with electricity point of view of physics , hence I only have a general idea of it so can you explain what is "eddies of electricity" mean in the answer? Thank you very much $\endgroup$
    – Naveen V
    Feb 17 at 15:23
  • $\begingroup$ The fundamental concept is that magnetic fields can induce currents in a moving conductive fluid, which in turn polarizes the fluid and reciprocally changes the magnetic field itself. Eddies means electrical flow in a circle, It is powered by the motion of the fluid in the magnetic field, which allows a conducting fluid to convert heat and rotation into a magnetic field. $\endgroup$
    – James K
    Feb 17 at 15:27
  • $\begingroup$ Ah thanks now i can understand $\endgroup$
    – Naveen V
    Feb 17 at 18:03

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