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Analysis of the nature of interaction of a magnetized star with the surrounding plasma allows us to write an approximate evolution equation for the angular momentum of a magnetic rotator in the general form (Lipunov, 1982a)
where is a specific angular momentum applied by the accretion matter to the rotator. This quantity is given by
where is the radius of the inner disk edge, is the rotational frequency of the binary system, and (Illarionov and Sunyaev, 1975). The values of dimensionless factor , characteristic radius and the accretion rate in different regimes are presented in Table 3.
The evolution equation (4.10.2) is approximate. In practice, the situation with propellers and superpropellers is not yet clear. In Table 3 is the size of a magnetosphere whose value at the propeller stage is not known accurately and which may differ significantly from the standard expressions for the Alfvén radius.