Why Is the Field so Strong?
The rapid rotation, high temperature, and high magnetic field of a neutron star are all
a result of its gravitational collapse. Because angular momentum is conserved, a star
that was originally spinning slowly must spin very fast when it contracts down to neutron
star size (recall the analogy of the ice skater spinning faster when the arms are retracted).
Likewise, the magnetic field, which is trapped in the plasma, is condensed and
greatly intensified by the collapse. Finally, the very high temperature is also gravitational
in origin since the collapse converts large sums of gravitational potential energy to kinetic energy of the
neutron star.