We have performed an auto and cross spectral analysis of the electron density and magnetic field fluctuations recorded aboard ISEE 1 and 2 in the terrestrial magnetosheath far from the subsolar point. The data were obtained near 0600 local time and roughly equidistant from the magnetopause and the bow shock. The analysis shows the characteristic signature of mirror type modes when the mean magnetic field is draping the magnetopause, and of Alfv¿n type wave modes at other times. ¿ American Geophysicaly Union 1989