What Define the Polar Cap and Auroral Oval Magnetic Fluxes? Igor I. Alexeev (Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow, 119992 Russia) A dependence of the polar cap magnetic flux on the solar wind dynamic pressure and the interplanetary magnetic field was studied. The relation between polar cap magnetic flux and the polar oval size at ionospheric level was obtained. The received functions based on the paraboloid magnetosphere model calculations. The average or quiet condition was used for compare the theoretical results with the UV images of the EarthÕs polar region from the Polar and IMAGE spacecrafts. The model calculations give us possibility to find not only the average polar cap magnetic flux but also the extreme values of the polar cap and auroral oval magnetic fluxes. These values can be reached in the course of the severe magnetic storm. The secular variation of the polar cap connected with secular variation of the EarthÕs dipole field was demonstrated by the model calculations. _______________ Presented at the August 2003 AGU Chapman Conference, Helsinki, Finland