Magnetic variations measured at College, Alaska (L=5,6), contain a low-amplitude, intermittent tone near 5 mHz. The tone shows a regular variation in frequency throughout the day with the shortest periods (highest frequencies) near local noon and the longest periods (lowest frequencies) in the midnight sector. The wave train is composed of a superposition of individual packets which are not phase coherent. The polarization states of the pulses tend to be left hand, elliptical in the prenoon sector, becoming nearly liner in the afternoon-evening sector with the H component dominant. The short duration of individual packets and the lack of phase coherence imply that these pulsations are not the result of driven resonance but rather are the transient oscillations of the local field line which occur when there is an impulsive change in magnetospheric parmeters. Since both field and plasma conditions change onthelocal field line throughout the day, the natural response frequency of the field line will change as well. The level of diurnal variation is consistent with that calculated by Singer et al. (1981) using realistic field geometries. ¿ American Geophysical Union 1987