EFFECT OF NONUNIFORM IONOSPHERIC CONDUCTIVITY DISTRIBUTIONS ON PC3-5 MAGNETIC PULSATIONS - FAST-WAVE INCIDENCE

By assuming a simple model of the height-integrated ionospheric conduc tivity with a non-uniformity of sinusoidal type, the effect of the non -uniform ionosphere on geomagnetic pulsations in the Pc3-5 range trans mitted from the magnetosphere in the fast mode has been investigated. It is found that (1) the effect of non-uniformity becomes most signifi cant when the horizontal wave length of the incident wave lies in the neighborhood of the characteristic length of non-uniformity, (2) the e ffect of non-uniformity grows large as the wave period decreases and/o r the uniform part of the ionospheric conductivity increases, and (3) the effect of non-uniformity becomes more important as the conductivit y contrast grows large.