ON THE NATURE OF HIGH-FREQUENCY CUTOFFS IN SPECTRA OF PULSARS

Using values of frequencies nu-c for high-frequency cut-offs in 31 pulsars obtained by other authors, we have confirmed the relationship (obtained by us earlier) between nu-c and a period of pulsar P. The diagram nu-c (x) (x is relative angular distance between the line of sight and the center of radiation cone) was drawn. It is shown that pulsars with long periods are in the low left corner of this diagram. Some geometrical and physical reasons causing high-frequency cut-offs are analysed. The results can be explained by the model of thin plasma sheets. An interaction of these sheets causes a generation of Langmuir waves at distances approximately 10(8) cm from the center of the neutron star. Pulsars without high-frequency cut-offs can be described by a model yielding nu-c very close to the frequency of maximum in spectra of these pulsars.