ON THE ACCURACY OF ARRIVAL AZIMUTH DETERMINATION OF SPRITE-ASSOCIATEDLIGHTNING FLASHES BY EARTH-IONOSPHERE CAVITY RESONANCES

Horizontal magnetic field variations in the frequency range of the Ear th-ionosphere cavity resonances are observed at Silberborn, Germany, s imultaneous with 19 sprite-associated lightning flashes in the midwest ern United States, on July 15, 1995. The measured horizontal magnetic intensities are linearly related to the horizontal magnetic intensitie s of slow tails of radio atmospherics which were simultaneously record ed at Palmer Station, Antarctica. Enhancement of the Earth-ionosphere cavity resonances is verified by spectral analysis, and the measured a rrival azimuths are in agreement with the expected orientation of the Poynting vector along the great-circle path. The estimated accuracy of the arrival azimuth determination is on the order of +/-5 degrees.