Dynamics of the power spectrum of occurrence frequency of precipitations in the auroral ionosphere during the descending phase and at a minimum of cycle 22 of solar activity

The results of an analysis of the power spectrum of the occurrence frequenc y for precipitations of energetic electrons (E > 40 keV) recorded by a riom eter at Tixie station (32 MHz; phi (M) = 65.2; L = 5.6) during the descendi ng phase and at a minimum of solar-activity cycle 22 are presented. It has been demonstrated that precipitations of energetic electrons were most freq uent in 1994. A joint analysis of the precipitation occurrence frequency, i nterplanetary medium parameters, and geomagnetic activity indices has shown a high correlation with the solar-wind velocity and K-p and D-st indices. Harmonics with periods of similar to6.5, 9, and 13.5 days have been reveale d in the occurrence frequency of the ionospheric riometric absorption.