Buried Magnetic Field in Accreting Neutron Star

The evolution of the neutron star magnetic field is correlated to the accretion physical process in the binary X-ray phase. It is assumed that the original strong magnetic field is buried by the accreted materials, which is on account of the ferromagnetic physical property of the accreted matter. The obtained theoretical conclusions of our model are that: (1) the magnetic field decays in the X-ray binary phase, and relates inversely to the accreted mass as M^-1, (2) The internal magnetic field strength still remains large although the surface field strength decays.