Origin of neutron star magnetic fields

Understand

Possible origins of the magnetic fields of neutron stars include inheritance from the main sequence progenitor and dynamo action at some stage of evolution of progenitor.

• Inheritance is not sufficient to explain the fields of magnetars.
• Energetic considerations point to differential rotation in the final stages of core collapse process as the most likely source of field generation, at least for magnetars.
• A runaway phase of exponential growth is needed to achieve sufficient field amplification during relevant phase of core collapse; it can probably be provided by a some form of magnetorotational instability.