Fine structure of Pc 1 pulsations: 2. Theoretical interpretation

In an earlier letter STAWehrlin et al., 1973!, experimental evidence was given that demonstrated that aimost all the Pc 1 events do present a fine structure and that strongly suggests that this fine structure is a consequence of nonlinear phenomena taking place inside the magnetosphere. Furthermore, it was shown that the amplitude reached by the mother'' line when the daughter'' appears is significantly lower than the final saturation level of both the mother and the daughter lines. In this letter a tentative interpretntion of both the frequency separation between the different lines and their saturation level is given. Other possible mechanisms are also discussed. (auth)