1. Magnetic field evolution of accreting neutron stars Ya.N. Istomin P.N. Lebedev Physical Institute, Moscow, Russia

4. Accreting electric current

6. Depth of penetration into the crust

8. Critical magnetic field

9. Superconducting vortices

11. There exists the minimal magnetic field

12. Conclusion: • 1. We found the real mechanism of reducing the core magnetic field creating by superconducting protons. • 2. Magnetic field evolution of neutron stars • can give information about their internal structure.