The azimuthal structure of field-aligned current (FAC) systems is one of the target subjects of the Freja satellite's magnetometer observation. In the event of May 28, 1993, the satellite observed large-amplitude fluctuations of the latitudinal, as well as the longitudinal, magnetic field components along a postmidnight-to-morning orbit. By combining radar and ground magnetometer data, we inferred that the associated FAC system has a periodic structure consisting of multiple FAC inclinded significantly from the azimuthal (east-west) direction and moving westward and possibly poleward. Such a structure may be interpreted in terms of the meandering of an auroral electrojet, and perhaps as the ionospheric projection of boundary waves. ¿ American Geophysical Union 1994