Magnetometric data of north-american and Greenland station chains are compared with measurements of plasma parameters and magnetic fields aboard the IMP-8, ISEE-1.2, GOES-5.6 and IRM. For the sign-changeable IMF Bz-component having the oscillation form in the range of 5 to 20 min and with a regular amplitude of about 5 nT on October 29, 1985 the cross-correlation relationship to dayside high-latitude pulsations of the ground magnetic field is revealed. On the three station chains in the near noon sector of 9-15 LT we obtained the latitude-longitudinal distribution of oscillation phases which is in correspondence with the inclined and quasi-field aligned propagation of Alfven waves in different parts of the magnetosphere. The inclined phase oscillation fronts are formed in the 10–14 LT sector in the region of maximum dispersion of lengths of geomagnetic force lines. It is supposed that in this intermediate region between Alfven waves falling (running away) on the subauroral ionosphere and Alfven waves running (falling) from the polar cap at southern (northern) IMF the power-exchangeable process which is typical for the entry layer in the magnetopause takes place. Perhaps, in this case the pulsations penetrating from solar wind into the magnetosphere are the earlier unknown magnifestation of the magnetopause reaction to the IMF fluctuations. In the oscillation sense the reaction is reversible when the sign of Bz-component changes in the above-mentioned range of periods.