High resolution HF radar observations of ULF waves in the ionosphere are possible by artificially generating irregularities using the EISCAT heater at Troms¿, Norway. The line-of-sight velocities from the CUTLASS radars have been combined for the first time to form bistatic flow vectors during a ULF wave, generating ionospheric electric field measurements with a higher accuracy than ever previously recorded by any instrument. A high-m wave observed in the ionosphere exhibits a frequency which is a harmonic of that of a low-m field line resonance which is observed simultaneously in the ionosphere and at the ground. The high-m pulsation resembles a class of particle driven wave previously recorded on VHF radars. These results are consistent with recent HF radar observations of small scale waves possessing similar characteristics to field line resonances and with the theory that the low-m wave may be driving the high-m wave through a non-linear Kelvin-Helmholtz instability. ¿ 1999 American Geophysical Union