The dynamics of quasi-periodic ripples in the high-latitude F-region

This study extends the investigation of quasi-periodic ripples in F-region electron content reported by Birch and Hargreaves (2020a) to determine their flow velocity wavelength, using data from EISCAT Svalbard radars (the 42m antenna being field-aligned 32m scanning a circular pattern at fixed angle field). The were extracted between altitudes 213 389 km noon midnight sectors bandpass filter which reduces noise component while removing long-term trends. These found have an average periodicity about 21 min sector 27 night. Using line-of-sight data, they also propagate 467 m/s westerly direction with wavelength 581 km, night 283 southerly 454 km. directions compare favourably modelled plasma flows SuperDARN network coherent scatter radars. • Observations density made sectors. frequency fluctuations has been deduced height range speed selected UT intervals velocity. From these results, determined.