Radial magnetometric demagnetizing factor of thin disks

The radial magnetometric demagnetizing factor N-mr of a disk is calculated from the corresponding axial factor N-ma as a function of the ratio of thickness to diameter t/d and the susceptibility of material chi by the formula N-ma(t/d, chi = chi*) + 2N(mr)[t/d, chi = -chi*/(1 + chi*)] = 1 + delta (t/d, chi*). This formula is derived from the magnetostatic laws with a correction (\ delta \ much less than 1) based on known values of N-ma and N-mr for chi* = infinity. The accuracy of the N-mr thus obtained is estimated to be better than 1%, which satisfies most practical needs.