Design and Simulation Analysis of Space Active Hydrogen Maser Multi-segment C-field

In order to reduce the relative change rate of the transition frequency of the hydrogen masers caused by the inhomogeneous C field, two designs of C field components, three-segment solenoids and four sets of coils, are proposed. Using the high-order expansion of the magnetic field on the axis, the ampere-turn ratio and the solenoid spacing are calculated when the three-segment solenoid with L=0.05-0.5 constructs a uniform magnetic field. The finite element analysis of the magnetic field is carried out with L=0.2-0.45, and the magnetic field non-uniformity distribution with different widths is given. Among them, the maximum non-uniformity with L=0.45 in the storage bubble area is 0.105%, and the corresponding relative change rate of transition frequency is 1.02×10^-13. Using the same method, the ampere-turn ratio and spacing between coils when four or five sets of coils construct a uniform magnetic field are calculated, and the finite element simulation of the magnetic field in the coil is carried out, and the non-uniformity distribution is given. The maximum non-uniformity of the magnetic field in the storage bubble region in the four sets of coils is 0.066%, and the corresponding transition frequency relative change rate is 6.42×10^-14.